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COPY(7) 				   SQL Commands 				  COPY(7)

       COPY - copy data between files and tables

       COPY table [ ( column [, ...] ) ]
	   FROM { 'filename' | stdin }
	   [ [ WITH ]
		 [ BINARY ]
		 [ OIDS ]
		 [ DELIMITER [ AS ] 'delimiter' ]
		 [ NULL [ AS ] 'null string' ] ]
       COPY table [ ( column [, ...] ) ]
	   TO { 'filename' | stdout }
	   [ [ WITH ]
		 [ BINARY ]
		 [ OIDS ]
		 [ DELIMITER [ AS ] 'delimiter' ]
		 [ NULL [ AS ] 'null string' ] ]

       table  The name (possibly schema-qualified) of an existing table.

       column An  optional list of columns to be copied. If no column list is specified, all col-
	      umns will be used.

	      The absolute Unix path name of the input or output file.

       stdin  Specifies that input comes from the client application.

       stdout Specifies that output goes to the client application.

       BINARY Changes the behavior of field formatting, forcing all data to be stored or read  in
	      binary  format rather than as text. You can not specify DELIMITER or NULL in binary

       OIDS   Specifies copying the internal object id (OID) for each row.

	      The single character that separates fields within each row (line) of the file.

       null string
	      The string that represents a NULL value. The default is ``\N''  (backslash-N).  You
	      might prefer an empty string, for example.

	      Note: On a copy in, any data item that matches this string will be stored as a NULL
	      value, so you should make sure that you use the same string as  you  used  on  copy

       COPY   The copy completed successfully.

       ERROR: reason
	      The copy failed for the reason stated in the error message.

       COPY  moves  data between PostgreSQL tables and standard file-system files. COPY TO copies
       the contents of a table to a file, while COPY FROM copies data from  a  file  to  a  table
       (appending the data to whatever is in the table already).

       If  a  list of columns is specified, COPY will only copy the data in the specified columns
       to or from the file.  If there are any columns in the table that are  not  in  the  column
       list, COPY FROM will insert the default values for those columns.

       COPY with a file name instructs the PostgreSQL backend to directly read from or write to a
       file. The file must be accessible to the backend and the name must be specified	from  the
       viewpoint of the backend. When stdin or stdout is specified, data flows through the client
       frontend to the backend.

	      Tip: Do not confuse COPY with the psql instruction \copy. \copy invokes  COPY  FROM
	      stdin  or  COPY TO stdout, and then fetches/stores the data in a file accessible to
	      the psql client. Thus, file accessibility and access rights depend  on  the  client
	      rather than the backend when \copy is used.

       COPY can only be used with plain tables, not with views.

       The  BINARY  keyword will force all data to be stored/read as binary format rather than as
       text. It is somewhat faster than the normal copy command, but a binary copy  file  is  not
       portable across machine architectures.

       By  default,  a	text  copy uses a tab ("\t") character as a delimiter between fields. The
       field delimiter may be changed to any other single character with the  keyword  DELIMITER.
       Characters  in  data fields that happen to match the delimiter character will be backslash

       You must have select privilege on any table whose values are read by COPY TO,  and  insert
       privilege  on  a table into which values are being inserted by COPY FROM. The backend also
       needs appropriate Unix permissions for any file read or written by COPY.

       COPY FROM will invoke any triggers and check constraints on the	destination  table.  How-
       ever, it will not invoke rules.

       COPY  stops operation at the first error. This should not lead to problems in the event of
       a COPY TO, but the target relation will already have received earlier rows in a COPY FROM.
       These  rows  will not be visible or accessible, but they still occupy disk space. This may
       amount to a considerable amount of wasted disk space if the failure happened well  into	a
       large copy operation. You may wish to invoke VACUUM to recover the wasted space.

       Files  named  in  a  COPY  command are read or written directly by the backend, not by the
       client application. Therefore, they must reside on or be accessible to the database server
       machine,  not the client. They must be accessible to and readable or writable by the Post-
       greSQL user (the user ID the server runs as), not the client. COPY naming a file  is  only
       allowed to database superusers, since it allows reading or writing any file that the back-
       end has privileges to access.

	      Tip: The psql instruction \copy reads or writes files on the  client  machine  with
	      the client's permissions, so it is not restricted to superusers.

       It is recommended that the file name used in COPY always be specified as an absolute path.
       This is enforced by the backend in the case of COPY TO, but for COPY FROM you do have  the
       option  of  reading from a file specified by a relative path. The path will be interpreted
       relative to the backend's working directory (somewhere below $PGDATA),  not  the  client's
       working directory.

       When  COPY is used without the BINARY option, the file read or written is a text file with
       one line per table row.	Columns (attributes) in a row  are  separated  by  the	delimiter
       character.   The attribute values themselves are strings generated by the output function,
       or acceptable to the input function, of each attribute's data type.  The  specified  null-
       value  string is used in place of attributes that are NULL.  COPY FROM will raise an error
       if any line of the input file contains more or fewer columns than are expected.

       If OIDS is specified, the OID is read or written as the first column, preceding	the  user
       data  columns.  (An  error  is  raised if OIDS is specified for a table that does not have

       End of data can be represented by a single line containing just backslash-period (\.).  An
       end-of-data  marker  is not necessary when reading from a Unix file, since the end of file
       serves perfectly well; but an end marker must be provided when copying data to or  from	a
       client application.

       Backslash  characters (\) may be used in the COPY data to quote data characters that might
       otherwise be taken as row or column delimiters. In particular,  the  following  characters
       must  be  preceded  by a backslash if they appear as part of an attribute value: backslash
       itself, newline, and the current delimiter character.

       The following special backslash sequences are  recognized  by  COPY  FROM:  SequenceRepre-
       sents\bBackspace  (ASCII  8)\fForm  feed  (ASCII  12)\nNewline (ASCII 10)\rCarriage return
       (ASCII 13)\tTab (ASCII 9)\vVertical tab (ASCII  11)\digitsBackslash  followed  by  one  to
       three  octal digits specifies the character with that numeric code Presently, COPY TO will
       never emit an octal-digits backslash sequence, but it does use the other sequences  listed
       above for those control characters.

       Never put a backslash before a data character N or period (.). Such pairs will be mistaken
       for the default null string or the end-of-data marker, respectively. Any other backslashed
       character that is not mentioned in the above table will be taken to represent itself.

       It  is  strongly  recommended that applications generating COPY data convert data newlines
       and carriage returns to the \n and \r sequences respectively. At present  (PostgreSQL  7.2
       and older versions) it is possible to represent a data carriage return without any special
       quoting, and to represent a data newline by a backslash and newline. However, these repre-
       sentations will not be accepted by default in future releases.

       Note  that  the	end of each row is marked by a Unix-style newline ("\n"). Presently, COPY
       FROM will not behave as desired if given a file containing  DOS-  or  Mac-style	newlines.
       This is expected to change in future releases.

       The  file  format used for COPY BINARY changed in PostgreSQL v7.1. The new format consists
       of a file header, zero or more tuples, and a file trailer.

       The file header consists of 24 bytes of fixed fields, followed by a variable-length header
       extension area. The fixed fields are:

	      12-byte  sequence  PGBCOPY\n\377\r\n\0 --- note that the null is a required part of
	      the signature. (The signature is designed to allow  easy	identification	of  files
	      that have been munged by a non-8-bit-clean transfer. This signature will be changed
	      by newline-translation  filters,	dropped  nulls,  dropped  high	bits,  or  parity

       Integer layout field
	      int32  constant  0x01020304  in  source's  byte  order. Potentially, a reader could
	      engage in byte-flipping of subsequent fields if the wrong byte  order  is  detected

       Flags field
	      int32  bit  mask	to denote important aspects of the file format. Bits are numbered
	      from 0 (LSB) to 31 (MSB) --- note that this field is stored with	source's  endian-
	      ness, as are all subsequent integer fields. Bits 16-31 are reserved to denote crit-
	      ical file format issues; a reader should abort if it finds an unexpected bit set in
	      this  range. Bits 0-15 are reserved to signal backwards-compatible format issues; a
	      reader should simply ignore any unexpected bits set in this range.  Currently  only
	      one flag bit is defined, and the rest must be zero:

	      Bit 16 if 1, OIDs are included in the dump; if 0, not

       Header extension area length
	      int32  length  in  bytes of remainder of header, not including self. In the initial
	      version this will be zero, and the first tuple follows immediately. Future  changes
	      to  the  format  might  allow additional data to be present in the header. A reader
	      should silently skip over any header extension data it does not  know  what  to  do

       The  header extension area is envisioned to contain a sequence of self-identifying chunks.
       The flags field is not intended to tell readers what is in the  extension  area.  Specific
       design of header extension contents is left for a later release.

       This  design  allows  for both backwards-compatible header additions (add header extension
       chunks, or set low-order flag bits) and non-backwards-compatible changes  (set  high-order
       flag  bits  to  signal  such  changes,  and  add  supporting data to the extension area if

       Each tuple begins with an int16 count of the number of fields in  the  tuple.  (Presently,
       all  tuples in a table will have the same count, but that might not always be true.) Then,
       repeated for each field in the tuple, there is an int16 typlen word possibly  followed  by
       field data.  The typlen field is interpreted thus:

       Zero   Field is NULL. No data follows.

       > 0    Field is a fixed-length data type. Exactly N bytes of data follow the typlen word.

       -1     Field  is  a  varlena  data type. The next four bytes are the varlena header, which
	      contains the total value length including itself.

       < -1   Reserved for future use.

       For non-NULL fields, the reader can check that the typlen matches the expected typlen  for
       the  destination  column. This provides a simple but very useful check that the data is as

       There is no alignment padding or any other extra data between fields.  Note also that  the
       format  does  not  distinguish  whether a data type is pass-by-reference or pass-by-value.
       Both of these provisions are deliberate: they might help improve portability of the  files
       (although  of  course  endianness and floating-point-format issues can still keep you from
       moving a binary file across machines).

       If OIDs are included in the dump, the OID field immediately follows the field-count  word.
       It  is  a  normal field except that it's not included in the field-count. In particular it
       has a typlen --- this will allow handling of 4-byte vs 8-byte OIDs without too much  pain,
       and will allow OIDs to be shown as NULL if that ever proves desirable.

       The  file  trailer  consists  of an int16 word containing -1. This is easily distinguished
       from a tuple's field-count word.

       A reader should report an error if a field-count word is neither -1 nor the expected  num-
       ber  of columns. This provides an extra check against somehow getting out of sync with the

       The following example copies a table to standard output, using a vertical bar (|)  as  the
       field delimiter:

       COPY country TO stdout WITH DELIMITER '|';

       To copy data from a Unix file into the country table:

       COPY country FROM '/usr1/proj/bray/sql/country_data';

       Here  is a sample of data suitable for copying into a table from stdin (so it has the ter-
       mination sequence on the last line):

       AF      AFGHANISTAN
       AL      ALBANIA
       DZ      ALGERIA
       ZM      ZAMBIA
       ZW      ZIMBABWE

       Note that the white space on each line is actually a TAB.

       The following is the same data, output in binary format on a Linux/i586 machine. The  data
       is  shown  after filtering through the Unix utility od -c. The table has three fields; the
       first is char(2), the second is text, and the third is integer. All the rows have  a  null
       value in the third field.

       0000000	 P   G	 B   C	 O   P	 Y  \n 377  \r	\n  \0 004 003 002 001
       0000020	\0  \0	\0  \0	\0  \0	\0  \0 003  \0 377 377 006  \0	\0  \0
       0000040	 A   F 377 377 017  \0	\0  \0	 A   F	 G   H	 A   N	 I   S
       0000060	 T   A	 N  \0	\0 003	\0 377 377 006	\0  \0	\0   A	 L 377
       0000100 377  \v	\0  \0	\0   A	 L   B	 A   N	 I   A	\0  \0 003  \0
       0000120 377 377 006  \0	\0  \0	 D   Z 377 377	\v  \0	\0  \0	 A   L
       0000140	 G   E	 R   I	 A  \0	\0 003	\0 377 377 006	\0  \0	\0   Z
       0000160	 M 377 377  \n	\0  \0	\0   Z	 A   M	 B   I	 A  \0	\0 003
       0000200	\0 377 377 006	\0  \0	\0   Z	 W 377 377  \f	\0  \0	\0   Z
       0000220	 I   M	 B   A	 B   W	 E  \0	\0 377 377

       There is no COPY statement in SQL92.

       The following syntax was used by pre-7.3 applications and is still supported:

	   COPY [ BINARY ] table [ WITH OIDS ]
	       FROM { 'filename' | stdin }
	       [ [USING] DELIMITERS 'delimiter' ]
	       [ WITH NULL AS 'null string' ]
	   COPY [ BINARY ] table [ WITH OIDS ]
	       TO { 'filename' | stdout }
	       [ [USING] DELIMITERS 'delimiter' ]
	       [ WITH NULL AS 'null string' ]

SQL - Language Statements		    2002-11-22					  COPY(7)
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