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DBD::SQLite(3)		       User Contributed Perl Documentation		   DBD::SQLite(3)

NAME
       DBD::SQLite - Self-contained RDBMS in a DBI Driver

SYNOPSIS
	 use DBI;
	 my $dbh = DBI->connect("dbi:SQLite:dbname=$dbfile","","");

DESCRIPTION
       SQLite is a public domain file-based relational database engine that you can find at
       <http://www.sqlite.org/>.

       DBD::SQLite is a Perl DBI driver for SQLite, that includes the entire thing in the
       distribution.  So in order to get a fast transaction capable RDBMS working for your perl
       project you simply have to install this module, and nothing else.

       SQLite supports the following features:

       Implements a large subset of SQL92
	   See <http://www.sqlite.org/lang.html> for details.

       A complete DB in a single disk file
	   Everything for your database is stored in a single disk file, making it easier to move
	   things around than with DBD::CSV.

       Atomic commit and rollback
	   Yes, DBD::SQLite is small and light, but it supports full transactions!

       Extensible
	   User-defined aggregate or regular functions can be registered with the SQL parser.

       There's lots more to it, so please refer to the docs on the SQLite web page, listed above,
       for SQL details. Also refer to DBI for details on how to use DBI itself. The API works
       like every DBI module does.  However, currently many statement attributes are not
       implemented or are limited by the typeless nature of the SQLite database.

NOTABLE DIFFERENCES FROM OTHER DRIVERS
   Database Name Is A File Name
       SQLite creates a file per a database. You should pass the "path" of the database file
       (with or without a parent directory) in the DBI connection string (as a database "name"):

	 my $dbh = DBI->connect("dbi:SQLite:dbname=$dbfile","","");

       The file is opened in read/write mode, and will be created if it does not exist yet.

       Although the database is stored in a single file, the directory containing the database
       file must be writable by SQLite because the library will create several temporary files
       there.

       If the filename $dbfile is ":memory:", then a private, temporary in-memory database is
       created for the connection. This in-memory database will vanish when the database
       connection is closed.  It is handy for your library tests.

       Note that future versions of SQLite might make use of additional special filenames that
       begin with the ":" character. It is recommended that when a database filename actually
       does begin with a ":" character you should prefix the filename with a pathname such as
       "./" to avoid ambiguity.

       If the filename $dbfile is an empty string, then a private, temporary on-disk database
       will be created. This private database will be automatically deleted as soon as the
       database connection is closed.

   DBD::SQLite And File::Temp
       When you use File::Temp to create a temporary file/directory for SQLite databases, you
       need to remember:

       tempfile may be locked exclusively
	   You may want to use "tempfile()" to create a temporary database filename for
	   DBD::SQLite, but as noted in File::Temp's POD, this file may have an exclusive lock
	   under some operating systems (notably Mac OSX), and result in a "database is locked"
	   error.  To avoid this, set EXLOCK option to false when you call tempfile().

	     ($fh, $filename) = tempfile($template, EXLOCK => 0);

       CLEANUP may not work unless a database is disconnected
	   When you set CLEANUP option to true when you create a temporary directory with
	   "tempdir()" or "newdir()", you may have to disconnect databases explicitly before the
	   temporary directory is gone (notably under MS Windows).

       (The above is quoted from the pod of File::Temp.)

       If you don't need to keep or share a temporary database, use ":memory:" database instead.
       It's much handier and cleaner for ordinary testing.

   Accessing A Database With Other Tools
       To access the database from the command line, try using "dbish" which comes with the
       DBI::Shell module. Just type:

	 dbish dbi:SQLite:foo.db

       On the command line to access the file foo.db.

       Alternatively you can install SQLite from the link above without conflicting with
       DBD::SQLite and use the supplied "sqlite3" command line tool.

   Blobs
       As of version 1.11, blobs should "just work" in SQLite as text columns.	However this will
       cause the data to be treated as a string, so SQL statements such as length(x) will return
       the length of the column as a NUL terminated string, rather than the size of the blob in
       bytes. In order to store natively as a BLOB use the following code:

	 use DBI qw(:sql_types);
	 my $dbh = DBI->connect("dbi:SQLite:dbfile","","");

	 my $blob = `cat foo.jpg`;
	 my $sth = $dbh->prepare("INSERT INTO mytable VALUES (1, ?)");
	 $sth->bind_param(1, $blob, SQL_BLOB);
	 $sth->execute();

       And then retrieval just works:

	 $sth = $dbh->prepare("SELECT * FROM mytable WHERE id = 1");
	 $sth->execute();
	 my $row = $sth->fetch;
	 my $blobo = $row->[1];

	 # now $blobo == $blob

   Functions And Bind Parameters
       As of this writing, a SQL that compares a return value of a function with a numeric bind
       value like this doesn't work as you might expect.

	 my $sth = $dbh->prepare(q{
	   SELECT bar FROM foo GROUP BY bar HAVING count(*) > ?;
	 });
	 $sth->execute(5);

       This is because DBD::SQLite assumes that all the bind values are text (and should be
       quoted) by default. Thus the above statement becomes like this while executing:

	 SELECT bar FROM foo GROUP BY bar HAVING count(*) > "5";

       There are three workarounds for this.

       Use bind_param() explicitly
	   As shown above in the "BLOB" section, you can always use "bind_param()" to tell the
	   type of a bind value.

	     use DBI qw(:sql_types);  # Don't forget this

	     my $sth = $dbh->prepare(q{
	       SELECT bar FROM foo GROUP BY bar HAVING count(*) > ?;
	     });
	     $sth->bind_param(1, 5, SQL_INTEGER);
	     $sth->execute();

       Add zero to make it a number
	   This is somewhat weird, but works anyway.

	     my $sth = $dbh->prepare(q{
	       SELECT bar FROM foo GROUP BY bar HAVING count(*) > (? + 0);
	     });
	     $sth->execute(5);

       Set "sqlite_see_if_its_a_number" database handle attribute
	   As of version 1.32_02, you can use "sqlite_see_if_its_a_number" to let DBD::SQLite to
	   see if the bind values are numbers or not.

	     $dbh->{sqlite_see_if_its_a_number} = 1;
	     my $sth = $dbh->prepare(q{
	       SELECT bar FROM foo GROUP BY bar HAVING count(*) > ?;
	     });
	     $sth->execute(5);

	   You can set it to true when you connect to a database.

	     my $dbh = DBI->connect('dbi:SQLite:foo', undef, undef, {
	       AutoCommit => 1,
	       RaiseError => 1,
	       sqlite_see_if_its_a_number => 1,
	     });

	   This is the most straightforward solution, but as noted above, existing data in your
	   databases created by DBD::SQLite have not always been stored as numbers, so this
	   *might* cause other obscure problems. Use this sparingly when you handle existing
	   databases.  If you handle databases created by other tools like native "sqlite3"
	   command line tool, this attribute would help you.

   Placeholders
       SQLite supports several placeholder expressions, including "?"  and ":AAAA". Consult the
       DBI and sqlite documentation for details.

       <http://www.sqlite.org/lang_expr.html#varparam>

       Note that a question mark actually means a next unused (numbered) placeholder. You're
       advised not to use it with other (numbered or named) placeholders to avoid confusion.

	 my $sth = $dbh->prepare(
	   'update TABLE set a=?1 where b=?2 and a IS NOT ?1'
	 );
	 $sth->execute(1, 2);

   Foreign Keys
       BE PREPARED! WOLVES APPROACH!!

       SQLite has started supporting foreign key constraints since 3.6.19 (released on Oct 14,
       2009; bundled in DBD::SQLite 1.26_05).  To be exact, SQLite has long been able to parse a
       schema with foreign keys, but the constraints has not been enforced. Now you can issue a
       pragma actually to enable this feature and enforce the constraints.

       To do this, issue the following pragma (see below), preferably as soon as you connect to a
       database and you're not in a transaction:

	 $dbh->do("PRAGMA foreign_keys = ON");

       And you can explicitly disable the feature whenever you like by turning the pragma off:

	 $dbh->do("PRAGMA foreign_keys = OFF");

       As of this writing, this feature is disabled by default by the sqlite team, and by us, to
       secure backward compatibility, as this feature may break your applications, and actually
       broke some for us. If you have used a schema with foreign key constraints but haven't
       cared them much and supposed they're always ignored for SQLite, be prepared, and please do
       extensive testing to ensure that your applications will continue to work when the foreign
       keys support is enabled by default. It is very likely that the sqlite team will turn it
       default-on in the future, and we plan to do it NO LATER THAN they do so.

       See <http://www.sqlite.org/foreignkeys.html> for details.

   Pragma
       SQLite has a set of "Pragma"s to modify its operation or to query for its internal data.
       These are specific to SQLite and are not likely to work with other DBD libraries, but you
       may find some of these are quite useful, including:

       journal_mode
	   You can use this pragma to change the journal mode for SQLite databases, maybe for
	   better performance, or for compatibility.

	   Its default mode is "DELETE", which means SQLite uses a rollback journal to implement
	   transactions, and the journal is deleted at the conclusion of each transaction. If you
	   use "TRUNCATE" instead of "DELETE", the journal will be truncated, which is usually
	   much faster.

	   A "WAL" (write-ahead log) mode is introduced as of SQLite 3.7.0.  This mode is
	   persistent, and it stays in effect even after closing and reopening the database. In
	   other words, once the "WAL" mode is set in an application or in a test script, the
	   database becomes inaccessible by older clients. This tends to be an issue when you use
	   a system "sqlite3" executable under a conservative operating system.

	   To fix this, You need to issue "PRAGMA journal_mode = DELETE" (or "TRUNCATE")
	   beforehand, or install a newer version of "sqlite3".

       legacy_file_format
	   If you happen to need to create a SQLite database that will also be accessed by a very
	   old SQLite client (prior to 3.3.0 released in Jan. 2006), you need to set this pragma
	   to ON before you create a database.

       reverse_unordered_selects
	   You can set this pragma to ON to reverse the order of results of SELECT statements
	   without an ORDER BY clause so that you can see if applications are making invalid
	   assumptions about the result order.

	   Note that SQLite 3.7.15 (bundled with DBD::SQLite 1.38_02) enhanced its query
	   optimizer and the order of results of a SELECT statement without an ORDER BY clause
	   may be different from the one of the previous versions.

       synchronous
	   You can set set this pragma to OFF to make some of the operations in SQLite faster
	   with a possible risk of database corruption in the worst case. See also "Performance"
	   section below.

       See <http://www.sqlite.org/pragma.html> for more details.

   Transactions
       DBI/DBD::SQLite's transactions may be a bit confusing. They behave differently according
       to the status of the "AutoCommit" flag:

       When the AutoCommit flag is on
	   You're supposed to always use the auto-commit mode, except you explicitly begin a
	   transaction, and when the transaction ended, you're supposed to go back to the auto-
	   commit mode. To begin a transaction, call "begin_work" method, or issue a "BEGIN"
	   statement. To end it, call "commit/rollback" methods, or issue the corresponding
	   statements.

	     $dbh->{AutoCommit} = 1;

	     $dbh->begin_work; # or $dbh->do('BEGIN TRANSACTION');

	     # $dbh->{AutoCommit} is turned off temporarily during a transaction;

	     $dbh->commit; # or $dbh->do('COMMIT');

	     # $dbh->{AutoCommit} is turned on again;

       When the AutoCommit flag is off
	   You're supposed to always use the transactional mode, until you explicitly turn on the
	   AutoCommit flag. You can explicitly issue a "BEGIN" statement (only when an actual
	   transaction has not begun yet) but you're not allowed to call "begin_work" method (if
	   you don't issue a "BEGIN", it will be issued internally).  You can commit or roll it
	   back freely. Another transaction will automatically begins if you execute another
	   statement.

	     $dbh->{AutoCommit} = 0;

	     # $dbh->do('BEGIN TRANSACTION') is not necessary, but possible

	     ...

	     $dbh->commit; # or $dbh->do('COMMIT');

	     # $dbh->{AutoCommit} stays intact;

	     $dbh->{AutoCommit} = 1;  # ends the transactional mode

       This "AutoCommit" mode is independent from the autocommit mode of the internal SQLite
       library, which always begins by a "BEGIN" statement, and ends by a "COMMIT" or a
       <ROLLBACK>.

   Transaction and Database Locking
       The default transaction behavior of SQLite is "deferred", that means, locks are not
       acquired until the first read or write operation, and thus it is possible that another
       thread or process could create a separate transaction and write to the database after the
       "BEGIN" on the current thread has executed, and eventually cause a "deadlock". To avoid
       this, DBD::SQLite internally issues a "BEGIN IMMEDIATE" when you begin a transaction by
       "begin_work" or under the "AutoCommit" mode (since 1.38_01).

       If you really need to turn off this feature for some reasons, set
       "sqlite_use_immediate_transaction" database handle attribute to false, and the default
       "deferred" transaction will be used.

	 my $dbh = DBI->connect("dbi:SQLite::memory:", "", "", {
	   sqlite_use_immediate_transaction => 0,
	 });

       See <http://sqlite.org/lockingv3.html> for locking details.

   "$sth->finish" and Transaction Rollback
       As the DBI doc says, you almost certainly do not need to call "finish" in DBI method if
       you fetch all rows (probably in a loop).  However, there are several exceptions to this
       rule, and rolling-back of an unfinished "SELECT" statement is one of such exceptional
       cases.

       SQLite prohibits "ROLLBACK" of unfinished "SELECT" statements in a transaction (See
       <http://sqlite.org/lang_transaction.html> for details). So you need to call "finish"
       before you issue a rollback.

	 $sth = $dbh->prepare("SELECT * FROM t");
	 $dbh->begin_work;
	 eval {
	     $sth->execute;
	     $row = $sth->fetch;
	     ...
	     die "For some reason";
	     ...
	 };
	 if($@) {
	    $sth->finish;  # You need this for SQLite
	    $dbh->rollback;
	 } else {
	    $dbh->commit;
	 }

   Processing Multiple Statements At A Time
       DBI's statement handle is not supposed to process multiple statements at a time. So if you
       pass a string that contains multiple statements (a "dump") to a statement handle (via
       "prepare" or "do"), DBD::SQLite only processes the first statement, and discards the rest.

       Since 1.30_01, you can retrieve those ignored (unprepared) statements via
       "$sth->{sqlite_unprepared_statements}". It usually contains nothing but white spaces, but
       if you really care, you can check this attribute to see if there's anything left undone.
       Also, if you set a "sqlite_allow_multiple_statements" attribute of a database handle to
       true when you connect to a database, "do" method automatically checks the
       "sqlite_unprepared_statements" attribute, and if it finds anything undone (even if what's
       left is just a single white space), it repeats the process again, to the end.

   Performance
       SQLite is fast, very fast. Matt processed his 72MB log file with it, inserting the data
       (400,000+ rows) by using transactions and only committing every 1000 rows (otherwise the
       insertion is quite slow), and then performing queries on the data.

       Queries like count(*) and avg(bytes) took fractions of a second to return, but what
       surprised him most of all was:

	 SELECT url, count(*) as count
	 FROM access_log
	 GROUP BY url
	 ORDER BY count desc
	 LIMIT 20

       To discover the top 20 hit URLs on the site (<http://axkit.org>), and it returned within 2
       seconds. He was seriously considering switching his log analysis code to use this little
       speed demon!

       Oh yeah, and that was with no indexes on the table, on a 400MHz PIII.

       For best performance be sure to tune your hdparm settings if you are using linux. Also you
       might want to set:

	 PRAGMA synchronous = OFF

       Which will prevent sqlite from doing fsync's when writing (which slows down non-
       transactional writes significantly) at the expense of some peace of mind. Also try playing
       with the cache_size pragma.

       The memory usage of SQLite can also be tuned using the cache_size pragma.

	 $dbh->do("PRAGMA cache_size = 800000");

       The above will allocate 800M for DB cache; the default is 2M.  Your sweet spot probably
       lies somewhere in between.

DRIVER PRIVATE ATTRIBUTES
   Database Handle Attributes
       sqlite_version
	   Returns the version of the SQLite library which DBD::SQLite is using, e.g., "2.8.0".
	   Can only be read.

       sqlite_unicode
	   If set to a true value, DBD::SQLite will turn the UTF-8 flag on for all text strings
	   coming out of the database (this feature is currently disabled for perl < 5.8.5). For
	   more details on the UTF-8 flag see perlunicode. The default is for the UTF-8 flag to
	   be turned off.

	   Also note that due to some bizarreness in SQLite's type system (see
	   <http://www.sqlite.org/datatype3.html>), if you want to retain blob-style behavior for
	   some columns under "$dbh->{sqlite_unicode} = 1" (say, to store images in the
	   database), you have to state so explicitly using the 3-argument form of "bind_param"
	   in DBI when doing updates:

	     use DBI qw(:sql_types);
	     $dbh->{sqlite_unicode} = 1;
	     my $sth = $dbh->prepare("INSERT INTO mytable (blobcolumn) VALUES (?)");

	     # Binary_data will be stored as is.
	     $sth->bind_param(1, $binary_data, SQL_BLOB);

	   Defining the column type as "BLOB" in the DDL is not sufficient.

	   This attribute was originally named as "unicode", and renamed to "sqlite_unicode" for
	   integrity since version 1.26_06. Old "unicode" attribute is still accessible but will
	   be deprecated in the near future.

       sqlite_allow_multiple_statements
	   If you set this to true, "do" method will process multiple statements at one go. This
	   may be handy, but with performance penalty. See above for details.

       sqlite_use_immediate_transaction
	   If you set this to true, DBD::SQLite tries to issue a "begin immediate transaction"
	   (instead of "begin transaction") when necessary. See above for details.

	   As of version 1.38_01, this attribute is set to true by default.  If you really need
	   to use "deferred" transactions for some reasons, set this to false explicitly.

       sqlite_see_if_its_a_number
	   If you set this to true, DBD::SQLite tries to see if the bind values are number or
	   not, and does not quote if they are numbers. See above for details.

   Statement Handle Attributes
       sqlite_unprepared_statements
	   Returns an unprepared part of the statement you pass to "prepare".  Typically this
	   contains nothing but white spaces after a semicolon.  See above for details.

METHODS
       See also to the DBI documentation for the details of other common methods.

   table_info
	 $sth = $dbh->table_info(undef, $schema, $table, $type, \%attr);

       Returns all tables and schemas (databases) as specified in "table_info" in DBI.	The
       schema and table arguments will do a "LIKE" search. You can specify an ESCAPE character by
       including an 'Escape' attribute in \%attr. The $type argument accepts a comma separated
       list of the following types 'TABLE', 'VIEW', 'LOCAL TEMPORARY' and 'SYSTEM TABLE' (by
       default all are returned).  Note that a statement handle is returned, and not a direct
       list of tables.

       The following fields are returned:

       TABLE_CAT: Always NULL, as SQLite does not have the concept of catalogs.

       TABLE_SCHEM: The name of the schema (database) that the table or view is in. The default
       schema is 'main', temporary tables are in 'temp' and other databases will be in the name
       given when the database was attached.

       TABLE_NAME: The name of the table or view.

       TABLE_TYPE: The type of object returned. Will be one of 'TABLE', 'VIEW', 'LOCAL TEMPORARY'
       or 'SYSTEM TABLE'.

   primary_key, primary_key_info
	 @names = $dbh->primary_key(undef, $schema, $table);
	 $sth	= $dbh->primary_key_info(undef, $schema, $table, \%attr);

       You can retrieve primary key names or more detailed information.  As noted above, SQLite
       does not have the concept of catalogs, so the first argument of the methods is usually
       "undef", and you'll usually set "undef" for the second one (unless you want to know the
       primary keys of temporary tables).

   foreign_key_info
	 $sth = $dbh->foreign_key_info(undef, $pk_schema, $pk_table,
				       undef, $fk_schema, $fk_table);

       Returns information about foreign key constraints, as specified in "foreign_key_info" in
       DBI, but with some limitations :

       o   information in rows returned by the $sth is incomplete with respect to the
	   "foreign_key_info" in DBI specification. All requested fields are present, but the
	   content is "undef" for some of them.

       The following nonempty fields are returned :

       PKTABLE_NAME: The primary (unique) key table identifier.

       PKCOLUMN_NAME: The primary (unique) key column identifier.

       FKTABLE_NAME: The foreign key table identifier.

       FKCOLUMN_NAME: The foreign key column identifier.

       KEY_SEQ: The column sequence number (starting with 1), when several columns belong to a
       same constraint.

       UPDATE_RULE: The referential action for the UPDATE rule.  The following codes are defined:

	 CASCADE	      0
	 RESTRICT	      1
	 SET NULL	      2
	 NO ACTION	      3
	 SET DEFAULT	      4

       Default is 3 ('NO ACTION').

       DELETE_RULE: The referential action for the DELETE rule.  The codes are the same as for
       UPDATE_RULE.

       Unfortunately, the DEFERRABILITY field is always "undef"; as a matter of fact,
       deferrability clauses are supported by SQLite, but they can't be reported because the
       "PRAGMA foreign_key_list" tells nothing about them.

       UNIQUE_OR_PRIMARY: Whether the column is primary or unique.

       Note: foreign key support in SQLite must be explicitly turned on through a "PRAGMA"
       command; see "Foreign keys" earlier in this manual.

   ping
	 my $bool = $dbh->ping;

       returns true if the database file exists (or the database is in-memory), and the database
       connection is active.

DRIVER PRIVATE METHODS
       The following methods can be called via the func() method with a little tweak, but the use
       of func() method is now discouraged by the DBI author for various reasons (see DBI's
       document
       <http://search.cpan.org/dist/DBI/lib/DBI/DBD.pm#Using_install_method()_to_expose_driver-private_methods>
       for details). So, if you're using DBI >= 1.608, use these "sqlite_" methods. If you need
       to use an older DBI, you can call these like this:

	 $dbh->func( ..., "(method name without sqlite_ prefix)" );

       Exception: "sqlite_trace" should always be called as is, even with "func()" method (to
       avoid conflict with DBI's trace() method).

	 $dbh->func( ..., "sqlite_trace");

   $dbh->sqlite_last_insert_rowid()
       This method returns the last inserted rowid. If you specify an INTEGER PRIMARY KEY as the
       first column in your table, that is the column that is returned.  Otherwise, it is the
       hidden ROWID column. See the sqlite docs for details.

       Generally you should not be using this method. Use the DBI last_insert_id method instead.
       The usage of this is:

	 $h->last_insert_id($catalog, $schema, $table_name, $field_name [, \%attr ])

       Running "$h->last_insert_id("","","","")" is the equivalent of running
       "$dbh->sqlite_last_insert_rowid()" directly.

   $dbh->sqlite_db_filename()
       Retrieve the current (main) database filename. If the database is in-memory or temporary,
       this returns "undef".

   $dbh->sqlite_busy_timeout()
       Retrieve the current busy timeout.

   $dbh->sqlite_busy_timeout( $ms )
       Set the current busy timeout. The timeout is in milliseconds.

   $dbh->sqlite_create_function( $name, $argc, $code_ref )
       This method will register a new function which will be usable in an SQL query. The
       method's parameters are:

       $name
	   The name of the function. This is the name of the function as it will be used from
	   SQL.

       $argc
	   The number of arguments taken by the function. If this number is -1, the function can
	   take any number of arguments.

       $code_ref
	   This should be a reference to the function's implementation.

       For example, here is how to define a now() function which returns the current number of
       seconds since the epoch:

	 $dbh->sqlite_create_function( 'now', 0, sub { return time } );

       After this, it could be use from SQL as:

	 INSERT INTO mytable ( now() );

       REGEXP function

       SQLite includes syntactic support for an infix operator 'REGEXP', but without any
       implementation. The "DBD::SQLite" driver automatically registers an implementation that
       performs standard perl regular expression matching, using current locale. So for example
       you can search for words starting with an 'A' with a query like

	 SELECT * from table WHERE column REGEXP '\bA\w+'

       If you want case-insensitive searching, use perl regex flags, like this :

	 SELECT * from table WHERE column REGEXP '(?i:\bA\w+)'

       The default REGEXP implementation can be overridden through the "create_function" API
       described above.

       Note that regexp matching will not use SQLite indices, but will iterate over all rows, so
       it could be quite costly in terms of performance.

   $dbh->sqlite_create_collation( $name, $code_ref )
       This method manually registers a new function which will be usable in an SQL query as a
       COLLATE option for sorting. Such functions can also be registered automatically on demand:
       see section "COLLATION FUNCTIONS" below.

       The method's parameters are:

       $name
	   The name of the function exposed to SQL.

       $code_ref
	   Reference to the function's implementation.	The driver will check that this is a
	   proper sorting function.

   $dbh->sqlite_collation_needed( $code_ref )
       This method manually registers a callback function that will be invoked whenever an
       undefined collation sequence is required from an SQL statement. The callback is invoked as

	 $code_ref->($dbh, $collation_name)

       and should register the desired collation using "sqlite_create_collation".

       An initial callback is already registered by "DBD::SQLite", so for most common cases it
       will be simpler to just add your collation sequences in the %DBD::SQLite::COLLATION hash
       (see section "COLLATION FUNCTIONS" below).

   $dbh->sqlite_create_aggregate( $name, $argc, $pkg )
       This method will register a new aggregate function which can then be used from SQL. The
       method's parameters are:

       $name
	   The name of the aggregate function, this is the name under which the function will be
	   available from SQL.

       $argc
	   This is an integer which tells the SQL parser how many arguments the function takes.
	   If that number is -1, the function can take any number of arguments.

       $pkg
	   This is the package which implements the aggregator interface.

       The aggregator interface consists of defining three methods:

       new()
	   This method will be called once to create an object which should be used to aggregate
	   the rows in a particular group. The step() and finalize() methods will be called upon
	   the reference return by the method.

       step(@_)
	   This method will be called once for each row in the aggregate.

       finalize()
	   This method will be called once all rows in the aggregate were processed and it should
	   return the aggregate function's result. When there is no rows in the aggregate,
	   finalize() will be called right after new().

       Here is a simple aggregate function which returns the variance (example adapted from
       pysqlite):

	 package variance;

	 sub new { bless [], shift; }

	 sub step {
	     my ( $self, $value ) = @_;

	     push @$self, $value;
	 }

	 sub finalize {
	     my $self = $_[0];

	     my $n = @$self;

	     # Variance is NULL unless there is more than one row
	     return undef unless $n || $n == 1;

	     my $mu = 0;
	     foreach my $v ( @$self ) {
		 $mu += $v;
	     }
	     $mu /= $n;

	     my $sigma = 0;
	     foreach my $v ( @$self ) {
		 $sigma += ($v - $mu)**2;
	     }
	     $sigma = $sigma / ($n - 1);

	     return $sigma;
	 }

	 $dbh->sqlite_create_aggregate( "variance", 1, 'variance' );

       The aggregate function can then be used as:

	 SELECT group_name, variance(score)
	 FROM results
	 GROUP BY group_name;

       For more examples, see the DBD::SQLite::Cookbook.

   $dbh->sqlite_progress_handler( $n_opcodes, $code_ref )
       This method registers a handler to be invoked periodically during long running calls to
       SQLite.

       An example use for this interface is to keep a GUI updated during a large query. The
       parameters are:

       $n_opcodes
	   The progress handler is invoked once for every $n_opcodes virtual machine opcodes in
	   SQLite.

       $code_ref
	   Reference to the handler subroutine.  If the progress handler returns non-zero, the
	   SQLite operation is interrupted. This feature can be used to implement a "Cancel"
	   button on a GUI dialog box.

	   Set this argument to "undef" if you want to unregister a previous progress handler.

   $dbh->sqlite_commit_hook( $code_ref )
       This method registers a callback function to be invoked whenever a transaction is
       committed. Any callback set by a previous call to "sqlite_commit_hook" is overridden. A
       reference to the previous callback (if any) is returned.  Registering an "undef" disables
       the callback.

       When the commit hook callback returns zero, the commit operation is allowed to continue
       normally. If the callback returns non-zero, then the commit is converted into a rollback
       (in that case, any attempt to explicitly call "$dbh->rollback()" afterwards would yield an
       error).

   $dbh->sqlite_rollback_hook( $code_ref )
       This method registers a callback function to be invoked whenever a transaction is rolled
       back. Any callback set by a previous call to "sqlite_rollback_hook" is overridden. A
       reference to the previous callback (if any) is returned.  Registering an "undef" disables
       the callback.

   $dbh->sqlite_update_hook( $code_ref )
       This method registers a callback function to be invoked whenever a row is updated,
       inserted or deleted. Any callback set by a previous call to "sqlite_update_hook" is
       overridden. A reference to the previous callback (if any) is returned.  Registering an
       "undef" disables the callback.

       The callback will be called as

	 $code_ref->($action_code, $database, $table, $rowid)

       where

       $action_code
	   is an integer equal to either "DBD::SQLite::INSERT", "DBD::SQLite::DELETE" or
	   "DBD::SQLite::UPDATE" (see "Action Codes");

       $database
	   is the name of the database containing the affected row;

       $table
	   is the name of the table containing the affected row;

       $rowid
	   is the unique 64-bit signed integer key of the affected row within that table.

   $dbh->sqlite_set_authorizer( $code_ref )
       This method registers an authorizer callback to be invoked whenever SQL statements are
       being compiled by the "prepare" in DBI method.  The authorizer callback should return
       "DBD::SQLite::OK" to allow the action, "DBD::SQLite::IGNORE" to disallow the specific
       action but allow the SQL statement to continue to be compiled, or "DBD::SQLite::DENY" to
       cause the entire SQL statement to be rejected with an error. If the authorizer callback
       returns any other value, then "prepare" call that triggered the authorizer will fail with
       an error message.

       An authorizer is used when preparing SQL statements from an untrusted source, to ensure
       that the SQL statements do not try to access data they are not allowed to see, or that
       they do not try to execute malicious statements that damage the database. For example, an
       application may allow a user to enter arbitrary SQL queries for evaluation by a database.
       But the application does not want the user to be able to make arbitrary changes to the
       database. An authorizer could then be put in place while the user-entered SQL is being
       prepared that disallows everything except SELECT statements.

       The callback will be called as

	 $code_ref->($action_code, $string1, $string2, $database, $trigger_or_view)

       where

       $action_code
	   is an integer that specifies what action is being authorized (see "Action Codes").

       $string1, $string2
	   are strings that depend on the action code (see "Action Codes").

       $database
	   is the name of the database ("main", "temp", etc.) if applicable.

       $trigger_or_view
	   is the name of the inner-most trigger or view that is responsible for the access
	   attempt, or "undef" if this access attempt is directly from top-level SQL code.

   $dbh->sqlite_backup_from_file( $filename )
       This method accesses the SQLite Online Backup API, and will take a backup of the named
       database file, copying it to, and overwriting, your current database connection. This can
       be particularly handy if your current connection is to the special :memory: database, and
       you wish to populate it from an existing DB.

   $dbh->sqlite_backup_to_file( $filename )
       This method accesses the SQLite Online Backup API, and will take a backup of the currently
       connected database, and write it out to the named file.

   $dbh->sqlite_enable_load_extension( $bool )
       Calling this method with a true value enables loading (external) sqlite3 extensions. After
       the call, you can load extensions like this:

	 $dbh->sqlite_enable_load_extension(1);
	 $sth = $dbh->prepare("select load_extension('libsqlitefunctions.so')")
	 or die "Cannot prepare: " . $dbh->errstr();

   $dbh->sqlite_load_extension( $file, $proc )
       Loading an extension by a select statement (with the "load_extension" sqlite3 function
       like above) has some limitations. If you need to, say, create other functions from an
       extension, use this method. $file (a path to the extension) is mandatory, and $proc (an
       entry point name) is optional. You need to call "sqlite_enable_load_extension" before
       calling "sqlite_load_extension".

   $dbh->sqlite_trace( $code_ref )
       This method registers a trace callback to be invoked whenever SQL statements are being
       run.

       The callback will be called as

	 $code_ref->($statement)

       where

       $statement
	   is a UTF-8 rendering of the SQL statement text as the statement first begins
	   executing.

       Additional callbacks might occur as each triggered subprogram is entered. The callbacks
       for triggers contain a UTF-8 SQL comment that identifies the trigger.

       See also "TRACING" in DBI for better tracing options.

   $dbh->sqlite_profile( $code_ref )
       This method registers a profile callback to be invoked whenever a SQL statement finishes.

       The callback will be called as

	 $code_ref->($statement, $elapsed_time)

       where

       $statement
	   is the original statement text (without bind parameters).

       $elapsed_time
	   is an estimate of wall-clock time of how long that statement took to run (in
	   milliseconds).

       This method is considered experimental and is subject to change in future versions of
       SQLite.

       See also DBI::Profile for better profiling options.

   $dbh->sqlite_table_column_metadata( $dbname, $tablename, $columnname )
       is for internal use only.

   DBD::SQLite::compile_options()
       Returns an array of compile options (available since sqlite 3.6.23, bundled in DBD::SQLite
       1.30_01), or an empty array if the bundled library is old or compiled with
       SQLITE_OMIT_COMPILEOPTION_DIAGS.

   DBD::SQLite::sqlite_status()
       Returns a hash reference that holds a set of status information of SQLite runtime such as
       memory usage or page cache usage (see
       <http://www.sqlite.org/c3ref/c_status_malloc_count.html> for details). Each of the entry
       contains the current value and the highwater value.

	 my $status = DBD::SQLite::sqlite_status();
	 my $cur  = $status->{memory_used}{current};
	 my $high = $status->{memory_used}{highwater};

       You may also pass 0 as an argument to reset the status.

   $dbh->sqlite_db_status()
       Returns a hash reference that holds a set of status information of database connection
       such as cache usage. See <http://www.sqlite.org/c3ref/c_dbstatus_options.html> for
       details. You may also pass 0 as an argument to reset the status.

   $sth->sqlite_st_status()
       Returns a hash reference that holds a set of status information of SQLite statement handle
       such as full table scan count. See <http://www.sqlite.org/c3ref/c_stmtstatus_counter.html>
       for details. Statement status only holds the current value.

	 my $status = $sth->sqlite_st_status();
	 my $cur = $status->{fullscan_step};

       You may also pass 0 as an argument to reset the status.

DRIVER CONSTANTS
       A subset of SQLite C constants are made available to Perl, because they may be needed when
       writing hooks or authorizer callbacks. For accessing such constants, the "DBD::SQLite"
       module must be explicitly "use"d at compile time. For example, an authorizer that forbids
       any DELETE operation would be written as follows :

	 use DBD::SQLite;
	 $dbh->sqlite_set_authorizer(sub {
	   my $action_code = shift;
	   return $action_code == DBD::SQLite::DELETE ? DBD::SQLite::DENY
						      : DBD::SQLite::OK;
	 });

       The list of constants implemented in "DBD::SQLite" is given below; more information can be
       found ad at <http://www.sqlite.org/c3ref/constlist.html>.

   Authorizer Return Codes
	 OK
	 DENY
	 IGNORE

   Action Codes
       The "set_authorizer" method registers a callback function that is invoked to authorize
       certain SQL statement actions. The first parameter to the callback is an integer code that
       specifies what action is being authorized. The second and third parameters to the callback
       are strings, the meaning of which varies according to the action code. Below is the list
       of action codes, together with their associated strings.

	 # constant		 string1	 string2
	 # ========		 =======	 =======
	 CREATE_INDEX		 Index Name	 Table Name
	 CREATE_TABLE		 Table Name	 undef
	 CREATE_TEMP_INDEX	 Index Name	 Table Name
	 CREATE_TEMP_TABLE	 Table Name	 undef
	 CREATE_TEMP_TRIGGER	 Trigger Name	 Table Name
	 CREATE_TEMP_VIEW	 View Name	 undef
	 CREATE_TRIGGER 	 Trigger Name	 Table Name
	 CREATE_VIEW		 View Name	 undef
	 DELETE 		 Table Name	 undef
	 DROP_INDEX		 Index Name	 Table Name
	 DROP_TABLE		 Table Name	 undef
	 DROP_TEMP_INDEX	 Index Name	 Table Name
	 DROP_TEMP_TABLE	 Table Name	 undef
	 DROP_TEMP_TRIGGER	 Trigger Name	 Table Name
	 DROP_TEMP_VIEW 	 View Name	 undef
	 DROP_TRIGGER		 Trigger Name	 Table Name
	 DROP_VIEW		 View Name	 undef
	 INSERT 		 Table Name	 undef
	 PRAGMA 		 Pragma Name	 1st arg or undef
	 READ			 Table Name	 Column Name
	 SELECT 		 undef		 undef
	 TRANSACTION		 Operation	 undef
	 UPDATE 		 Table Name	 Column Name
	 ATTACH 		 Filename	 undef
	 DETACH 		 Database Name	 undef
	 ALTER_TABLE		 Database Name	 Table Name
	 REINDEX		 Index Name	 undef
	 ANALYZE		 Table Name	 undef
	 CREATE_VTABLE		 Table Name	 Module Name
	 DROP_VTABLE		 Table Name	 Module Name
	 FUNCTION		 undef		 Function Name
	 SAVEPOINT		 Operation	 Savepoint Name

COLLATION FUNCTIONS
   Definition
       SQLite v3 provides the ability for users to supply arbitrary comparison functions, known
       as user-defined "collation sequences" or "collating functions", to be used for comparing
       two text values.  <http://www.sqlite.org/datatype3.html#collation> explains how collations
       are used in various SQL expressions.

   Builtin collation sequences
       The following collation sequences are builtin within SQLite :

       BINARY
	   Compares string data using memcmp(), regardless of text encoding.

       NOCASE
	   The same as binary, except the 26 upper case characters of ASCII are folded to their
	   lower case equivalents before the comparison is performed. Note that only ASCII
	   characters are case folded. SQLite does not attempt to do full UTF case folding due to
	   the size of the tables required.

       RTRIM
	   The same as binary, except that trailing space characters are ignored.

       In addition, "DBD::SQLite" automatically installs the following collation sequences :

       perl
	   corresponds to the Perl "cmp" operator

       perllocale
	   Perl "cmp" operator, in a context where "use locale" is activated.

   Usage
       You can write for example

	 CREATE TABLE foo(
	     txt1 COLLATE perl,
	     txt2 COLLATE perllocale,
	     txt3 COLLATE nocase
	 )

       or

	 SELECT * FROM foo ORDER BY name COLLATE perllocale

   Unicode handling
       If the attribute "$dbh->{sqlite_unicode}" is set, strings coming from the database and
       passed to the collation function will be properly tagged with the utf8 flag; but this only
       works if the "sqlite_unicode" attribute is set before the first call to a perl collation
       sequence . The recommended way to activate unicode is to set the parameter at connection
       time :

	 my $dbh = DBI->connect(
	     "dbi:SQLite:dbname=foo", "", "",
	     {
		 RaiseError	=> 1,
		 sqlite_unicode => 1,
	     }
	 );

   Adding user-defined collations
       The native SQLite API for adding user-defined collations is exposed through methods
       "sqlite_create_collation" and "sqlite_collation_needed".

       To avoid calling these functions every time a $dbh handle is created, "DBD::SQLite" offers
       a simpler interface through the %DBD::SQLite::COLLATION hash : just insert your own
       collation functions in that hash, and whenever an unknown collation name is encountered in
       SQL, the appropriate collation function will be loaded on demand from the hash. For
       example, here is a way to sort text values regardless of their accented characters :

	 use DBD::SQLite;
	 $DBD::SQLite::COLLATION{no_accents} = sub {
	   my ( $a, $b ) = map lc, @_;
	   tr[XXXXXXXXXXXXXXXXXXXXXXXXXXXX]
	     [aaaaaacdeeeeiiiinoooooouuuuy] for $a, $b;
	   $a cmp $b;
	 };
	 my $dbh  = DBI->connect("dbi:SQLite:dbname=dbfile");
	 my $sql  = "SELECT ... FROM ... ORDER BY ... COLLATE no_accents");
	 my $rows = $dbh->selectall_arrayref($sql);

       The builtin "perl" or "perllocale" collations are predefined in that same hash.

       The COLLATION hash is a global registry within the current process; hence there is a risk
       of undesired side-effects. Therefore, to prevent action at distance, the hash is
       implemented as a "write-only" hash, that will happily accept new entries, but will raise
       an exception if any attempt is made to override or delete a existing entry (including the
       builtin "perl" and "perllocale").

       If you really, really need to change or delete an entry, you can always grab the tied
       object underneath %DBD::SQLite::COLLATION --- but don't do that unless you really know
       what you are doing. Also observe that changes in the global hash will not modify existing
       collations in existing database handles: it will only affect new requests for collations.
       In other words, if you want to change the behaviour of a collation within an existing
       $dbh, you need to call the "create_collation" method directly.

FULLTEXT SEARCH
       The FTS extension module within SQLite allows users to create special tables with a built-
       in full-text index (hereafter "FTS tables"). The full-text index allows the user to
       efficiently query the database for all rows that contain one or more instances of a
       specified word (hereafter a "token"), even if the table contains many large documents.

   Short introduction to FTS
       The first full-text search modules for SQLite were called "FTS1" and "FTS2" and are now
       obsolete. The latest recommended module is "FTS4"; however the former module "FTS3" is
       still supporter.  Detailed documentation for both "FTS4" and "FTS3" can be found at
       <http://www.sqlite.org/fts3.html>, including explanations about the differences between
       these two versions.

       Here is a very short example of using FTS :

	 $dbh->do(<<"") or die DBI::errstr;
	 CREATE VIRTUAL TABLE fts_example USING fts4(content)

	 my $sth = $dbh->prepare("INSERT INTO fts_example(content) VALUES (?))");
	 $sth->execute($_) foreach @docs_to_insert;

	 my $results = $dbh->selectall_arrayref(<<"");
	 SELECT docid, snippet(content) FROM fts_example WHERE content MATCH 'foo'

       The key points in this example are :

       o   The syntax for creating FTS tables is

	     CREATE VIRTUAL TABLE <table_name> USING fts4(<columns>)

	   where "<columns>" is a list of column names. Columns may be typed, but the type
	   information is ignored. If no columns are specified, the default is a single column
	   named "content".  In addition, FTS tables have an implicit column called "docid" (or
	   also "rowid") for numbering the stored documents.

       o   Statements for inserting, updating or deleting records use the same syntax as for
	   regular SQLite tables.

       o   Full-text searches are specified with the "MATCH" operator, and an operand which may
	   be a single word, a word prefix ending with '*', a list of words, a "phrase query" in
	   double quotes, or a boolean combination of the above.

       o   The builtin function "snippet(...)" builds a formatted excerpt of the document text,
	   where the words pertaining to the query are highlighted.

       There are many more details to building and searching FTS tables, so we strongly invite
       you to read the full documentation at <http://www.sqlite.org/fts3.html>.

       Incompatible change : starting from version 1.31, "DBD::SQLite" uses the new, recommended
       "Enhanced Query Syntax" for binary set operators (AND, OR, NOT, possibly nested with
       parenthesis). Previous versions of "DBD::SQLite" used the "Standard Query Syntax" (see
       <http://www.sqlite.org/fts3.html#section_3_2>).	Unfortunately this is a compilation
       switch, so it cannot be tuned at runtime; however, since FTS3 was never advertised in
       versions prior to 1.31, the change should be invisible to the vast majority of
       "DBD::SQLite" users. If, however, there are any applications that nevertheless were built
       using the "Standard Query" syntax, they have to be migrated, because the precedence of the
       "OR" operator has changed. Conversion from old to new syntax can be automated through
       DBD::SQLite::FTS3Transitional, published in a separate distribution.

   Tokenizers
       The behaviour of full-text indexes strongly depends on how documents are split into
       tokens; therefore FTS table declarations can explicitly specify how to perform
       tokenization:

	 CREATE ... USING fts4(<columns>, tokenize=<tokenizer>)

       where "<tokenizer>" is a sequence of space-separated words that triggers a specific
       tokenizer. Tokenizers can be SQLite builtins, written in C code, or Perl tokenizers.  Both
       are as explained below.

       SQLite builtin tokenizers

       SQLite comes with three builtin tokenizers :

       simple
	   Under the simple tokenizer, a term is a contiguous sequence of eligible characters,
	   where eligible characters are all alphanumeric characters, the "_" character, and all
	   characters with UTF codepoints greater than or equal to 128. All other characters are
	   discarded when splitting a document into terms. They serve only to separate adjacent
	   terms.

	   All uppercase characters within the ASCII range (UTF codepoints less than 128), are
	   transformed to their lowercase equivalents as part of the tokenization process. Thus,
	   full-text queries are case-insensitive when using the simple tokenizer.

       porter
	   The porter tokenizer uses the same rules to separate the input document into terms,
	   but as well as folding all terms to lower case it uses the Porter Stemming algorithm
	   to reduce related English language words to a common root.

       icu If SQLite is compiled with the SQLITE_ENABLE_ICU pre-processor symbol defined, then
	   there exists a built-in tokenizer named "icu" implemented using the ICU library, and
	   taking an ICU locale identifier as argument (such as "tr_TR" for Turkish as used in
	   Turkey, or "en_AU" for English as used in Australia). For example:

	     CREATE VIRTUAL TABLE thai_text USING fts4(text, tokenize=icu th_TH)

	   The ICU tokenizer implementation is very simple. It splits the input text according to
	   the ICU rules for finding word boundaries and discards any tokens that consist
	   entirely of white-space. This may be suitable for some applications in some locales,
	   but not all. If more complex processing is required, for example to implement stemming
	   or discard punctuation, use the perl tokenizer as explained below.

       Perl tokenizers

       In addition to the builtin SQLite tokenizers, "DBD::SQLite" implements a perl tokenizer,
       that can hook to any tokenizing algorithm written in Perl. This is specified as follows :

	 CREATE ... USING fts4(<columns>, tokenize=perl '<perl_function>')

       where "<perl_function>" is a fully qualified Perl function name (i.e. prefixed by the name
       of the package in which that function is declared). So for example if the function is
       "my_func" in the main program, write

	 CREATE ... USING fts4(<columns>, tokenize=perl 'main::my_func')

       That function should return a code reference that takes a string as single argument, and
       returns an iterator (another function), which returns a tuple "($term, $len, $start, $end,
       $index)" for each term. Here is a simple example that tokenizes on words according to the
       current perl locale

	 sub locale_tokenizer {
	   return sub {
	     my $string = shift;

	     use locale;
	     my $regex	    = qr/\w+/;
	     my $term_index = 0;

	     return sub { # closure
	       $string =~ /$regex/g or return; # either match, or no more token
	       my ($start, $end) = ($-[0], $+[0]);
	       my $len		 = $end-$start;
	       my $term 	 = substr($string, $start, $len);
	       return ($term, $len, $start, $end, $term_index++);
	     }
	   };
	 }

       There must be three levels of subs, in a kind of "Russian dolls" structure, because :

       o   the external, named sub is called whenever accessing a FTS table with that tokenizer

       o   the inner, anonymous sub is called whenever a new string needs to be tokenized (either
	   for inserting new text into the table, or for analyzing a query).

       o   the innermost, anonymous sub is called repeatedly for retrieving all terms within that
	   string.

       Instead of writing tokenizers by hand, you can grab one of those already implemented in
       the Search::Tokenizer module. For example, if you want ignore differences between accented
       characters, you can write :

	 use Search::Tokenizer;
	 $dbh->do(<<"") or die DBI::errstr;
	 CREATE ... USING fts4(<columns>,
			       tokenize=perl 'Search::Tokenizer::unaccent')

       Alternatively, you can use "new" in Search::Tokenizer to build your own tokenizer.

   Incomplete handling of utf8 characters
       The current FTS implementation in SQLite is far from complete with respect to utf8
       handling : in particular, variable-length characters are not treated correctly by the
       builtin functions "offsets()" and "snippet()".

   Database space for FTS
       By default, FTS stores a complete copy of the indexed documents, together with the
       fulltext index. On a large collection of documents, this can consume quite a lot of disk
       space. However, FTS has some options for compressing the documents, or even for not
       storing them at all -- see <http://www.sqlite.org/fts3.html#fts4_options>.

R* TREE SUPPORT
       The RTREE extension module within SQLite adds support for creating a R-Tree, a special
       index for range and multidimensional queries.  This allows users to create tables that can
       be loaded with (as an example) geospatial data such as latitude/longitude coordinates for
       buildings within a city :

	 CREATE VIRTUAL TABLE city_buildings USING rtree(
	    id, 	      -- Integer primary key
	    minLong, maxLong, -- Minimum and maximum longitude
	    minLat, maxLat    -- Minimum and maximum latitude
	 );

       then query which buildings overlap or are contained within a specified region:

	 # IDs that are contained within query coordinates
	 my $contained_sql = <<"";
	 SELECT id FROM try_rtree
	    WHERE  minLong >= ? AND maxLong <= ?
	    AND    minLat  >= ? AND maxLat  <= ?

	 # ... and those that overlap query coordinates
	 my $overlap_sql = <<"";
	 SELECT id FROM try_rtree
	    WHERE    maxLong >= ? AND minLong <= ?
	    AND      maxLat  >= ? AND minLat  <= ?

	 my $contained = $dbh->selectcol_arrayref($contained_sql,undef,
			       $minLong, $maxLong, $minLat, $maxLat);

	 my $overlapping = $dbh->selectcol_arrayref($overlap_sql,undef,
			       $minLong, $maxLong, $minLat, $maxLat);

       For more detail, please see the SQLite R-Tree page (<http://www.sqlite.org/rtree.html>).
       Note that custom R-Tree queries using callbacks, as mentioned in the prior link, have not
       been implemented yet.

FOR DBD::SQLITE EXTENSION AUTHORS
       Since 1.30_01, you can retrieve the bundled sqlite C source and/or header like this:

	 use File::ShareDir 'dist_dir';
	 use File::Spec::Functions 'catfile';

	 # the whole sqlite3.h header
	 my $sqlite3_h = catfile(dist_dir('DBD-SQLite'), 'sqlite3.h');

	 # or only a particular header, amalgamated in sqlite3.c
	 my $what_i_want = 'parse.h';
	 my $sqlite3_c = catfile(dist_dir('DBD-SQLite'), 'sqlite3.c');
	 open my $fh, '<', $sqlite3_c or die $!;
	 my $code = do { local $/; <$fh> };
	 my ($parse_h) = $code =~ m{(
	   /\*+[ ]Begin[ ]file[ ]$what_i_want[ ]\*+
	   .+?
	   /\*+[ ]End[ ]of[ ]$what_i_want[ ]\*+/
	 )}sx;
	 open my $out, '>', $what_i_want or die $!;
	 print $out $parse_h;
	 close $out;

       You usually want to use this in your extension's "Makefile.PL", and you may want to add
       DBD::SQLite to your extension's "CONFIGURE_REQUIRES" to ensure your extension users use
       the same C source/header they use to build DBD::SQLite itself (instead of the ones
       installed in their system).

TO DO
       The following items remain to be done.

   Leak Detection
       Implement one or more leak detection tests that only run during AUTOMATED_TESTING and
       RELEASE_TESTING and validate that none of the C code we work with leaks.

   Stream API for Blobs
       Reading/writing into blobs using "sqlite2_blob_open" / "sqlite2_blob_close".

   Flags for sqlite3_open_v2
       Support the full API of sqlite3_open_v2 (flags for opening the file).

   Support for custom callbacks for R-Tree queries
       Custom queries of a R-Tree index using a callback are possible with the SQLite C API
       (<http://www.sqlite.org/rtree.html>), so one could potentially use a callback that
       narrowed the result set down based on a specific need, such as querying for overlapping
       circles.

SUPPORT
       Bugs should be reported via the CPAN bug tracker at

       <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=DBD-SQLite>

       Note that bugs of bundled sqlite library (i.e. bugs in "sqlite3.[ch]") should be reported
       to the sqlite developers at sqlite.org via their bug tracker or via their mailing list.

AUTHORS
       Matt Sergeant <matt@sergeant.org>

       Francis J. Lacoste <flacoste@logreport.org>

       Wolfgang Sourdeau <wolfgang@logreport.org>

       Adam Kennedy <adamk@cpan.org>

       Max Maischein <corion@cpan.org>

       Laurent Dami <dami@cpan.org>

       Kenichi Ishigaki <ishigaki@cpan.org>

COPYRIGHT
       The bundled SQLite code in this distribution is Public Domain.

       DBD::SQLite is copyright 2002 - 2007 Matt Sergeant.

       Some parts copyright 2008 Francis J. Lacoste.

       Some parts copyright 2008 Wolfgang Sourdeau.

       Some parts copyright 2008 - 2013 Adam Kennedy.

       Some parts copyright 2009 - 2013 Kenichi Ishigaki.

       Some parts derived from DBD::SQLite::Amalgamation copyright 2008 Audrey Tang.

       This program is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself.

       The full text of the license can be found in the LICENSE file included with this module.

perl v5.16.3				    2013-06-09				   DBD::SQLite(3)
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