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ECPG(1) 						  PostgreSQL 9.2.7 Documentation						   ECPG(1)

ecpg - embedded SQL C preprocessor SYNOPSIS
ecpg [option...] file... DESCRIPTION
ecpg is the embedded SQL preprocessor for C programs. It converts C programs with embedded SQL statements to normal C code by replacing the SQL invocations with special function calls. The output files can then be processed with any C compiler tool chain. ecpg will convert each input file given on the command line to the corresponding C output file. Input files preferably have the extension .pgc, in which case the extension will be replaced by .c to determine the output file name. If the extension of the input file is not .pgc, then the output file name is computed by appending .c to the full file name. The output file name can also be overridden using the -o option. This reference page does not describe the embedded SQL language. See Chapter 33, ECPG - Embedded SQL in C, in the documentation for more information on that topic. OPTIONS
ecpg accepts the following command-line arguments: -c Automatically generate certain C code from SQL code. Currently, this works for EXEC SQL TYPE. -C mode Set a compatibility mode. mode can be INFORMIX or INFORMIX_SE. -D symbol Define a C preprocessor symbol. -h Parse a header file, this option includes otion -c. -i Parse system include files as well. -I directory Specify an additional include path, used to find files included via EXEC SQL INCLUDE. Defaults are . (current directory), /usr/local/include, the PostgreSQL include directory which is defined at compile time (default: /usr/local/pgsql/include), and /usr/include, in that order. -o filename Specifies that ecpg should write all its output to the given filename. -r option Selects run-time behavior. Option can be one of the following: no_indicator Do not use indicators but instead use special values to represent null values. Historically there have been databases using this approach. prepare Prepare all statements before using them. Libecpg will keep a cache of prepared statements and reuse a statement if it gets executed again. If the cache runs full, libecpg will free the least used statement. questionmarks Allow question mark as placeholder for compatibility reasons. This used to be the default long ago. --regression Run in regression testing mode. -t Turn on autocommit of transactions. In this mode, each SQL command is automatically committed unless it is inside an explicit transaction block. In the default mode, commands are committed only when EXEC SQL COMMIT is issued. -v Print additional information including the version and the "include" path. --version Print the ecpg version and exit. -?, --help Show help about ecpg command line arguments, and exit. NOTES
When compiling the preprocessed C code files, the compiler needs to be able to find the ECPG header files in the PostgreSQL include directory. Therefore, you might have to use the -I option when invoking the compiler (e.g., -I/usr/local/pgsql/include). Programs using C code with embedded SQL have to be linked against the libecpg library, for example using the linker options -L/usr/local/pgsql/lib -lecpg. The value of either of these directories that is appropriate for the installation can be found out using pg_config(1). EXAMPLES
If you have an embedded SQL C source file named prog1.pgc, you can create an executable program using the following sequence of commands: ecpg prog1.pgc cc -I/usr/local/pgsql/include -c prog1.c cc -o prog1 prog1.o -L/usr/local/pgsql/lib -lecpg PostgreSQL 9.2.7 2014-02-17 ECPG(1)

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BEGIN(7)						  PostgreSQL 9.2.7 Documentation						  BEGIN(7)

BEGIN - start a transaction block SYNOPSIS
BEGIN initiates a transaction block, that is, all statements after a BEGIN command will be executed in a single transaction until an explicit COMMIT(7) or ROLLBACK(7) is given. By default (without BEGIN), PostgreSQL executes transactions in "autocommit" mode, that is, each statement is executed in its own transaction and a commit is implicitly performed at the end of the statement (if execution was successful, otherwise a rollback is done). Statements are executed more quickly in a transaction block, because transaction start/commit requires significant CPU and disk activity. Execution of multiple statements inside a transaction is also useful to ensure consistency when making several related changes: other sessions will be unable to see the intermediate states wherein not all the related updates have been done. If the isolation level, read/write mode, or deferrable mode is specified, the new transaction has those characteristics, as if SET TRANSACTION (SET_TRANSACTION(7)) was executed. PARAMETERS
WORK, TRANSACTION Optional key words. They have no effect. Refer to SET TRANSACTION (SET_TRANSACTION(7)) for information on the meaning of the other parameters to this statement. NOTES
START TRANSACTION (START_TRANSACTION(7)) has the same functionality as BEGIN. Use COMMIT(7) or ROLLBACK(7) to terminate a transaction block. Issuing BEGIN when already inside a transaction block will provoke a warning message. The state of the transaction is not affected. To nest transactions within a transaction block, use savepoints (see SAVEPOINT(7)). For reasons of backwards compatibility, the commas between successive transaction_modes can be omitted. EXAMPLES
To begin a transaction block: BEGIN; COMPATIBILITY
BEGIN is a PostgreSQL language extension. It is equivalent to the SQL-standard command START TRANSACTION (START_TRANSACTION(7)), whose reference page contains additional compatibility information. The DEFERRABLE transaction_mode is a PostgreSQL language extension. Incidentally, the BEGIN key word is used for a different purpose in embedded SQL. You are advised to be careful about the transaction semantics when porting database applications. SEE ALSO
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