<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >COPY</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REV="MADE" HREF="mailto:pgsql-docs@postgresql.org"><LINK REL="HOME" TITLE="PostgreSQL 8.0.11 Documentation" HREF="index.html"><LINK REL="UP" TITLE="SQL Commands" HREF="sql-commands.html"><LINK REL="PREVIOUS" TITLE="COMMIT" HREF="sql-commit.html"><LINK REL="NEXT" TITLE="CREATE AGGREGATE" HREF="sql-createaggregate.html"><LINK REL="STYLESHEET" TYPE="text/css" HREF="stylesheet.css"><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"><META NAME="creation" CONTENT="2007-02-02T03:57:22"></HEAD ><BODY CLASS="REFENTRY" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="5" ALIGN="center" VALIGN="bottom" >PostgreSQL 8.0.11 Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="sql-commit.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="sql-commit.html" >Fast Backward</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="sql-createaggregate.html" >Fast Forward</A ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="sql-createaggregate.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SQL-COPY" ></A >COPY</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN38219" ></A ><H2 >Name</H2 >COPY -- copy data between a file and a table</DIV ><A NAME="AEN38222" ></A ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN38224" ></A ><H2 >Synopsis</H2 ><PRE CLASS="SYNOPSIS" >COPY <TT CLASS="REPLACEABLE" ><I >tablename</I ></TT > [ ( <TT CLASS="REPLACEABLE" ><I >column</I ></TT > [, ...] ) ] FROM { '<TT CLASS="REPLACEABLE" ><I >filename</I ></TT >' | STDIN } [ [ WITH ] [ BINARY ] [ OIDS ] [ DELIMITER [ AS ] '<TT CLASS="REPLACEABLE" ><I >delimiter</I ></TT >' ] [ NULL [ AS ] '<TT CLASS="REPLACEABLE" ><I >null string</I ></TT >' ] [ CSV [ QUOTE [ AS ] '<TT CLASS="REPLACEABLE" ><I >quote</I ></TT >' ] [ ESCAPE [ AS ] '<TT CLASS="REPLACEABLE" ><I >escape</I ></TT >' ] [ FORCE NOT NULL <TT CLASS="REPLACEABLE" ><I >column</I ></TT > [, ...] ] COPY <TT CLASS="REPLACEABLE" ><I >tablename</I ></TT > [ ( <TT CLASS="REPLACEABLE" ><I >column</I ></TT > [, ...] ) ] TO { '<TT CLASS="REPLACEABLE" ><I >filename</I ></TT >' | STDOUT } [ [ WITH ] [ BINARY ] [ OIDS ] [ DELIMITER [ AS ] '<TT CLASS="REPLACEABLE" ><I >delimiter</I ></TT >' ] [ NULL [ AS ] '<TT CLASS="REPLACEABLE" ><I >null string</I ></TT >' ] [ CSV [ QUOTE [ AS ] '<TT CLASS="REPLACEABLE" ><I >quote</I ></TT >' ] [ ESCAPE [ AS ] '<TT CLASS="REPLACEABLE" ><I >escape</I ></TT >' ] [ FORCE QUOTE <TT CLASS="REPLACEABLE" ><I >column</I ></TT > [, ...] ]</PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN38242" ></A ><H2 >Description</H2 ><P > <TT CLASS="COMMAND" >COPY</TT > moves data between <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > tables and standard file-system files. <TT CLASS="COMMAND" >COPY TO</TT > copies the contents of a table <SPAN CLASS="emphasis" ><I CLASS="EMPHASIS" >to</I ></SPAN > a file, while <TT CLASS="COMMAND" >COPY FROM</TT > copies data <SPAN CLASS="emphasis" ><I CLASS="EMPHASIS" >from</I ></SPAN > a file to a table (appending the data to whatever is in the table already). </P ><P > If a list of columns is specified, <TT CLASS="COMMAND" >COPY</TT > 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, <TT CLASS="COMMAND" >COPY FROM</TT > will insert the default values for those columns. </P ><P > <TT CLASS="COMMAND" >COPY</TT > with a file name instructs the <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > server to directly read from or write to a file. The file must be accessible to the server and the name must be specified from the viewpoint of the server. When <TT CLASS="LITERAL" >STDIN</TT > or <TT CLASS="LITERAL" >STDOUT</TT > is specified, data is transmitted via the connection between the client and the server. </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN38259" ></A ><H2 >Parameters</H2 ><P ></P ><DIV CLASS="VARIABLELIST" ><DL ><DT ><TT CLASS="REPLACEABLE" ><I >tablename</I ></TT ></DT ><DD ><P > The name (optionally schema-qualified) of an existing table. </P ></DD ><DT ><TT CLASS="REPLACEABLE" ><I >column</I ></TT ></DT ><DD ><P > An optional list of columns to be copied. If no column list is specified, all columns will be used. </P ></DD ><DT ><TT CLASS="REPLACEABLE" ><I >filename</I ></TT ></DT ><DD ><P > The absolute path name of the input or output file. </P ></DD ><DT ><TT CLASS="LITERAL" >STDIN</TT ></DT ><DD ><P > Specifies that input comes from the client application. </P ></DD ><DT ><TT CLASS="LITERAL" >STDOUT</TT ></DT ><DD ><P > Specifies that output goes to the client application. </P ></DD ><DT ><TT CLASS="LITERAL" >BINARY</TT ></DT ><DD ><P > Causes all data to be stored or read in binary format rather than as text. You cannot specify the <TT CLASS="OPTION" >DELIMITER</TT >, <TT CLASS="OPTION" >NULL</TT >, or <TT CLASS="OPTION" >CSV</TT > options in binary mode. </P ></DD ><DT ><TT CLASS="LITERAL" >OIDS</TT ></DT ><DD ><P > Specifies copying the OID for each row. (An error is raised if <TT CLASS="LITERAL" >OIDS</TT > is specified for a table that does not have OIDs.) </P ></DD ><DT ><TT CLASS="REPLACEABLE" ><I >delimiter</I ></TT ></DT ><DD ><P > The single character that separates columns within each row (line) of the file. The default is a tab character in text mode, a comma in <TT CLASS="LITERAL" >CSV</TT > mode. </P ></DD ><DT ><TT CLASS="REPLACEABLE" ><I >null string</I ></TT ></DT ><DD ><P > The string that represents a null value. The default is <TT CLASS="LITERAL" >\N</TT > (backslash-N) in text mode, and a empty value with no quotes in <TT CLASS="LITERAL" >CSV</TT > mode. You might prefer an empty string even in text mode for cases where you don't want to distinguish nulls from empty strings. </P ><DIV CLASS="NOTE" ><BLOCKQUOTE CLASS="NOTE" ><P ><B >Note: </B > When using <TT CLASS="COMMAND" >COPY FROM</TT >, 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 with <TT CLASS="COMMAND" >COPY TO</TT >. </P ></BLOCKQUOTE ></DIV ></DD ><DT ><TT CLASS="LITERAL" >CSV</TT ></DT ><DD ><P > Selects Comma Separated Value (<TT CLASS="LITERAL" >CSV</TT >) mode. </P ></DD ><DT ><TT CLASS="REPLACEABLE" ><I >quote</I ></TT ></DT ><DD ><P > Specifies the quotation character in <TT CLASS="LITERAL" >CSV</TT > mode. The default is double-quote. </P ></DD ><DT ><TT CLASS="REPLACEABLE" ><I >escape</I ></TT ></DT ><DD ><P > Specifies the character that should appear before a <TT CLASS="LITERAL" >QUOTE</TT > data character value in <TT CLASS="LITERAL" >CSV</TT > mode. The default is the <TT CLASS="LITERAL" >QUOTE</TT > value (usually double-quote). </P ></DD ><DT ><TT CLASS="LITERAL" >FORCE QUOTE</TT ></DT ><DD ><P > In <TT CLASS="LITERAL" >CSV</TT > <TT CLASS="COMMAND" >COPY TO</TT > mode, forces quoting to be used for all non-<TT CLASS="LITERAL" >NULL</TT > values in each specified column. <TT CLASS="LITERAL" >NULL</TT > output is never quoted. </P ></DD ><DT ><TT CLASS="LITERAL" >FORCE NOT NULL</TT ></DT ><DD ><P > In <TT CLASS="LITERAL" >CSV</TT > <TT CLASS="COMMAND" >COPY FROM</TT > mode, process each specified column as though it were quoted and hence not a <TT CLASS="LITERAL" >NULL</TT > value. For the default null string in <TT CLASS="LITERAL" >CSV</TT > mode (<TT CLASS="LITERAL" >''</TT >), this causes missing values to be input as zero-length strings. </P ></DD ></DL ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN38357" ></A ><H2 >Notes</H2 ><P > <TT CLASS="COMMAND" >COPY</TT > can only be used with plain tables, not with views. </P ><P > The <TT CLASS="LITERAL" >BINARY</TT > key word causes all data to be stored/read as binary format rather than as text. It is somewhat faster than the normal text mode, but a binary-format file is less portable across machine architectures and <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > versions. </P ><P > You must have select privilege on the table whose values are read by <TT CLASS="COMMAND" >COPY TO</TT >, and insert privilege on the table into which values are inserted by <TT CLASS="COMMAND" >COPY FROM</TT >. </P ><P > Files named in a <TT CLASS="COMMAND" >COPY</TT > command are read or written directly by the server, 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 <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > user (the user ID the server runs as), not the client. <TT CLASS="COMMAND" >COPY</TT > naming a file is only allowed to database superusers, since it allows reading or writing any file that the server has privileges to access. </P ><P > Do not confuse <TT CLASS="COMMAND" >COPY</TT > with the <SPAN CLASS="APPLICATION" >psql</SPAN > instruction <TT CLASS="COMMAND" >\copy</TT >. <TT CLASS="COMMAND" >\copy</TT > invokes <TT CLASS="COMMAND" >COPY FROM STDIN</TT > or <TT CLASS="COMMAND" >COPY TO STDOUT</TT >, and then fetches/stores the data in a file accessible to the <SPAN CLASS="APPLICATION" >psql</SPAN > client. Thus, file accessibility and access rights depend on the client rather than the server when <TT CLASS="COMMAND" >\copy</TT > is used. </P ><P > It is recommended that the file name used in <TT CLASS="COMMAND" >COPY</TT > always be specified as an absolute path. This is enforced by the server in the case of <TT CLASS="COMMAND" >COPY TO</TT >, but for <TT CLASS="COMMAND" >COPY FROM</TT > you do have the option of reading from a file specified by a relative path. The path will be interpreted relative to the working directory of the server process (somewhere below the data directory), not the client's working directory. </P ><P > <TT CLASS="COMMAND" >COPY FROM</TT > will invoke any triggers and check constraints on the destination table. However, it will not invoke rules. </P ><P > <TT CLASS="COMMAND" >COPY</TT > input and output is affected by <TT CLASS="VARNAME" >DateStyle</TT >. To ensure portability to other <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > installations that might use non-default <TT CLASS="VARNAME" >DateStyle</TT > settings, <TT CLASS="VARNAME" >DateStyle</TT > should be set to <TT CLASS="LITERAL" >ISO</TT > before using <TT CLASS="COMMAND" >COPY TO</TT >. </P ><P > <TT CLASS="COMMAND" >COPY</TT > stops operation at the first error. This should not lead to problems in the event of a <TT CLASS="COMMAND" >COPY TO</TT >, but the target table will already have received earlier rows in a <TT CLASS="COMMAND" >COPY FROM</TT >. 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 <TT CLASS="COMMAND" >VACUUM</TT > to recover the wasted space. </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN38399" ></A ><H2 >File Formats</H2 ><DIV CLASS="REFSECT2" ><A NAME="AEN38401" ></A ><H3 >Text Format</H3 ><P > When <TT CLASS="COMMAND" >COPY</TT > is used without the <TT CLASS="LITERAL" >BINARY</TT > or <TT CLASS="LITERAL" >CSV</TT > options, the data read or written is a text file with one line per table row. Columns in a row are separated by the delimiter character. The column values themselves are strings generated by the output function, or acceptable to the input function, of each attribute's data type. The specified null string is used in place of columns that are null. <TT CLASS="COMMAND" >COPY FROM</TT > will raise an error if any line of the input file contains more or fewer columns than are expected. If <TT CLASS="LITERAL" >OIDS</TT > is specified, the OID is read or written as the first column, preceding the user data columns. </P ><P > End of data can be represented by a single line containing just backslash-period (<TT CLASS="LITERAL" >\.</TT >). An end-of-data marker is not necessary when reading from a file, since the end of file serves perfectly well; it is needed only when copying data to or from client applications using pre-3.0 client protocol. </P ><P > Backslash characters (<TT CLASS="LITERAL" >\</TT >) may be used in the <TT CLASS="COMMAND" >COPY</TT > data to quote data characters that might otherwise be taken as row or column delimiters. In particular, the following characters <SPAN CLASS="emphasis" ><I CLASS="EMPHASIS" >must</I ></SPAN > be preceded by a backslash if they appear as part of a column value: backslash itself, newline, carriage return, and the current delimiter character. </P ><P > The specified null string is sent by <TT CLASS="COMMAND" >COPY TO</TT > without adding any backslashes; conversely, <TT CLASS="COMMAND" >COPY FROM</TT > matches the input against the null string before removing backslashes. Therefore, a null string such as <TT CLASS="LITERAL" >\N</TT > cannot be confused with the actual data value <TT CLASS="LITERAL" >\N</TT > (which would be represented as <TT CLASS="LITERAL" >\\N</TT >). </P ><P > The following special backslash sequences are recognized by <TT CLASS="COMMAND" >COPY FROM</TT >: <DIV CLASS="INFORMALTABLE" ><P ></P ><A NAME="AEN38423" ></A ><TABLE BORDER="1" CLASS="CALSTABLE" ><COL><COL><THEAD ><TR ><TH >Sequence</TH ><TH >Represents</TH ></TR ></THEAD ><TBODY ><TR ><TD ><TT CLASS="LITERAL" >\b</TT ></TD ><TD >Backspace (ASCII 8)</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >\f</TT ></TD ><TD >Form feed (ASCII 12)</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >\n</TT ></TD ><TD >Newline (ASCII 10)</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >\r</TT ></TD ><TD >Carriage return (ASCII 13)</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >\t</TT ></TD ><TD >Tab (ASCII 9)</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >\v</TT ></TD ><TD >Vertical tab (ASCII 11)</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >\</TT ><TT CLASS="REPLACEABLE" ><I >digits</I ></TT ></TD ><TD >Backslash followed by one to three octal digits specifies the character with that numeric code</TD ></TR ></TBODY ></TABLE ><P ></P ></DIV > Presently, <TT CLASS="COMMAND" >COPY TO</TT > will never emit an octal-digits backslash sequence, but it does use the other sequences listed above for those control characters. </P ><P > Any other backslashed character that is not mentioned in the above table will be taken to represent itself. However, beware of adding backslashes unnecessarily, since that might accidentally produce a string matching the end-of-data marker (<TT CLASS="LITERAL" >\.</TT >) or the null string (<TT CLASS="LITERAL" >\N</TT > by default). These strings will be recognized before any other backslash processing is done. </P ><P > It is strongly recommended that applications generating <TT CLASS="COMMAND" >COPY</TT > data convert data newlines and carriage returns to the <TT CLASS="LITERAL" >\n</TT > and <TT CLASS="LITERAL" >\r</TT > sequences respectively. At present it is possible to represent a data carriage return by a backslash and carriage return, and to represent a data newline by a backslash and newline. However, these representations might not be accepted in future releases. They are also highly vulnerable to corruption if the <TT CLASS="COMMAND" >COPY</TT > file is transferred across different machines (for example, from Unix to Windows or vice versa). </P ><P > <TT CLASS="COMMAND" >COPY TO</TT > will terminate each row with a Unix-style newline (<SPAN CLASS="QUOTE" >"<TT CLASS="LITERAL" >\n</TT >"</SPAN >). Servers running on Microsoft Windows instead output carriage return/newline (<SPAN CLASS="QUOTE" >"<TT CLASS="LITERAL" >\r\n</TT >"</SPAN >), but only for <TT CLASS="COMMAND" >COPY</TT > to a server file; for consistency across platforms, <TT CLASS="COMMAND" >COPY TO STDOUT</TT > always sends <SPAN CLASS="QUOTE" >"<TT CLASS="LITERAL" >\n</TT >"</SPAN > regardless of server platform. <TT CLASS="COMMAND" >COPY FROM</TT > can handle lines ending with newlines, carriage returns, or carriage return/newlines. To reduce the risk of error due to un-backslashed newlines or carriage returns that were meant as data, <TT CLASS="COMMAND" >COPY FROM</TT > will complain if the line endings in the input are not all alike. </P ></DIV ><DIV CLASS="REFSECT2" ><A NAME="AEN38480" ></A ><H3 >CSV Format</H3 ><P > This format is used for importing and exporting the Comma Separated Value (<TT CLASS="LITERAL" >CSV</TT >) file format used by many other programs, such as spreadsheets. Instead of the escaping used by <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN >'s standard text mode, it produces and recognises the common CSV escaping mechanism. </P ><P > The values in each record are separated by the <TT CLASS="LITERAL" >DELIMITER</TT > character. If the value contains the delimiter character, the <TT CLASS="LITERAL" >QUOTE</TT > character, the <TT CLASS="LITERAL" >NULL</TT > string, a carriage return, or line feed character, then the whole value is prefixed and suffixed by the <TT CLASS="LITERAL" >QUOTE</TT > character, and any occurrence within the value of a <TT CLASS="LITERAL" >QUOTE</TT > character or the <TT CLASS="LITERAL" >ESCAPE</TT > character is preceded by the escape character. You can also use <TT CLASS="LITERAL" >FORCE QUOTE</TT > to force quotes when outputting non-<TT CLASS="LITERAL" >NULL</TT > values in specific columns. </P ><P > The <TT CLASS="LITERAL" >CSV</TT > format has no standard way to distinguish a <TT CLASS="LITERAL" >NULL</TT > value from an empty string. <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN >'s <TT CLASS="COMMAND" >COPY</TT > handles this by quoting. A <TT CLASS="LITERAL" >NULL</TT > is output as the <TT CLASS="LITERAL" >NULL</TT > string and is not quoted, while a data value matching the <TT CLASS="LITERAL" >NULL</TT > string is quoted. Therefore, using the default settings, a <TT CLASS="LITERAL" >NULL</TT > is written as an unquoted empty string, while an empty string is written with double quotes (<TT CLASS="LITERAL" >""</TT >). Reading values follows similar rules. You can use <TT CLASS="LITERAL" >FORCE NOT NULL</TT > to prevent <TT CLASS="LITERAL" >NULL</TT > input comparisons for specific columns. </P ><DIV CLASS="NOTE" ><BLOCKQUOTE CLASS="NOTE" ><P ><B >Note: </B > CSV mode will both recognize and produce CSV files with quoted values containing embedded carriage returns and line feeds. Thus the files are not strictly one line per table row like text-mode files. However, <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > will reject <TT CLASS="COMMAND" >COPY</TT > input if any fields contain embedded line end character sequences that do not match the line ending convention used in the CSV file itself. It is generally safer to import data containing embedded line end characters using the text or binary formats rather than CSV. </P ></BLOCKQUOTE ></DIV ><DIV CLASS="NOTE" ><BLOCKQUOTE CLASS="NOTE" ><P ><B >Note: </B > Many programs produce strange and occasionally perverse CSV files, so the file format is more a convention than a standard. Thus you might encounter some files that cannot be imported using this mechanism, and <TT CLASS="COMMAND" >COPY</TT > might produce files that other programs cannot process. </P ></BLOCKQUOTE ></DIV ></DIV ><DIV CLASS="REFSECT2" ><A NAME="AEN38513" ></A ><H3 >Binary Format</H3 ><P > The file format used for <TT CLASS="COMMAND" >COPY BINARY</TT > changed in <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > 7.4. The new format consists of a file header, zero or more tuples containing the row data, and a file trailer. Headers and data are now in network byte order. </P ><DIV CLASS="REFSECT3" ><A NAME="AEN38518" ></A ><H4 >File Header</H4 ><P > The file header consists of 15 bytes of fixed fields, followed by a variable-length header extension area. The fixed fields are: <P ></P ></P><DIV CLASS="VARIABLELIST" ><DL ><DT >Signature</DT ><DD ><P >11-byte sequence <TT CLASS="LITERAL" >PGCOPY\n\377\r\n\0</TT > — note that the zero byte 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 end-of-line-translation filters, dropped zero bytes, dropped high bits, or parity changes.) </P ></DD ><DT >Flags field</DT ><DD ><P >32-bit integer bit mask to denote important aspects of the file format. Bits are numbered from 0 (<ACRONYM CLASS="ACRONYM" >LSB</ACRONYM >) to 31 (<ACRONYM CLASS="ACRONYM" >MSB</ACRONYM >). Note that this field is stored in network byte order (most significant byte first), as are all the integer fields used in the file format. Bits 16-31 are reserved to denote critical 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: <P ></P ></P><DIV CLASS="VARIABLELIST" ><DL ><DT >Bit 16</DT ><DD ><P > if 1, OIDs are included in the data; if 0, not </P ></DD ></DL ></DIV ><P> </P ></DD ><DT >Header extension area length</DT ><DD ><P >32-bit integer, length in bytes of remainder of header, not including self. Currently, this is 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 with. </P ></DD ></DL ></DIV ><P> </P ><P >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. </P ><P > 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 needed). </P ></DIV ><DIV CLASS="REFSECT3" ><A NAME="AEN38544" ></A ><H4 >Tuples</H4 ><P >Each tuple begins with a 16-bit integer 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 a 32-bit length word followed by that many bytes of field data. (The length word does not include itself, and can be zero.) As a special case, -1 indicates a NULL field value. No value bytes follow in the NULL case. </P ><P >There is no alignment padding or any other extra data between fields. </P ><P >Presently, all data values in a <TT CLASS="COMMAND" >COPY BINARY</TT > file are assumed to be in binary format (format code one). It is anticipated that a future extension may add a header field that allows per-column format codes to be specified. </P ><P >To determine the appropriate binary format for the actual tuple data you should consult the <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > source, in particular the <CODE CLASS="FUNCTION" >*send</CODE > and <CODE CLASS="FUNCTION" >*recv</CODE > functions for each column's data type (typically these functions are found in the <TT CLASS="FILENAME" >src/backend/utils/adt/</TT > directory of the source distribution). </P ><P >If OIDs are included in the file, 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 length word — 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. </P ></DIV ><DIV CLASS="REFSECT3" ><A NAME="AEN38556" ></A ><H4 >File Trailer</H4 ><P > The file trailer consists of a 16-bit integer word containing -1. This is easily distinguished from a tuple's field-count word. </P ><P > A reader should report an error if a field-count word is neither -1 nor the expected number of columns. This provides an extra check against somehow getting out of sync with the data. </P ></DIV ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN38560" ></A ><H2 >Examples</H2 ><P > The following example copies a table to the client using the vertical bar (<TT CLASS="LITERAL" >|</TT >) as the field delimiter: </P><PRE CLASS="PROGRAMLISTING" >COPY country TO STDOUT WITH DELIMITER '|';</PRE ><P> </P ><P > To copy data from a file into the <TT CLASS="LITERAL" >country</TT > table: </P><PRE CLASS="PROGRAMLISTING" >COPY country FROM '/usr1/proj/bray/sql/country_data';</PRE ><P> </P ><P > Here is a sample of data suitable for copying into a table from <TT CLASS="LITERAL" >STDIN</TT >: </P><PRE CLASS="PROGRAMLISTING" >AF AFGHANISTAN AL ALBANIA DZ ALGERIA ZM ZAMBIA ZW ZIMBABWE</PRE ><P> Note that the white space on each line is actually a tab character. </P ><P > The following is the same data, output in binary format. The data is shown after filtering through the Unix utility <TT CLASS="COMMAND" >od -c</TT >. The table has three columns; the first has type <TT CLASS="TYPE" >char(2)</TT >, the second has type <TT CLASS="TYPE" >text</TT >, and the third has type <TT CLASS="TYPE" >integer</TT >. All the rows have a null value in the third column. </P><PRE CLASS="PROGRAMLISTING" >0000000 P G C O P Y \n 377 \r \n \0 \0 \0 \0 \0 \0 0000020 \0 \0 \0 \0 003 \0 \0 \0 002 A F \0 \0 \0 013 A 0000040 F G H A N I S T A N 377 377 377 377 \0 003 0000060 \0 \0 \0 002 A L \0 \0 \0 007 A L B A N I 0000100 A 377 377 377 377 \0 003 \0 \0 \0 002 D Z \0 \0 \0 0000120 007 A L G E R I A 377 377 377 377 \0 003 \0 \0 0000140 \0 002 Z M \0 \0 \0 006 Z A M B I A 377 377 0000160 377 377 \0 003 \0 \0 \0 002 Z W \0 \0 \0 \b Z I 0000200 M B A B W E 377 377 377 377 377 377</PRE ><P> </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN38577" ></A ><H2 >Compatibility</H2 ><P > There is no <TT CLASS="COMMAND" >COPY</TT > statement in the SQL standard. </P ><P > The following syntax was used before <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > version 7.3 and is still supported: </P><PRE CLASS="SYNOPSIS" >COPY [ BINARY ] <TT CLASS="REPLACEABLE" ><I >tablename</I ></TT > [ WITH OIDS ] FROM { '<TT CLASS="REPLACEABLE" ><I >filename</I ></TT >' | STDIN } [ [USING] DELIMITERS '<TT CLASS="REPLACEABLE" ><I >delimiter</I ></TT >' ] [ WITH NULL AS '<TT CLASS="REPLACEABLE" ><I >null string</I ></TT >' ] COPY [ BINARY ] <TT CLASS="REPLACEABLE" ><I >tablename</I ></TT > [ WITH OIDS ] TO { '<TT CLASS="REPLACEABLE" ><I >filename</I ></TT >' | STDOUT } [ [USING] DELIMITERS '<TT CLASS="REPLACEABLE" ><I >delimiter</I ></TT >' ] [ WITH NULL AS '<TT CLASS="REPLACEABLE" ><I >null string</I ></TT >' ]</PRE ><P> </P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="sql-commit.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="sql-createaggregate.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >COMMIT</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="sql-commands.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >CREATE AGGREGATE</TD ></TR ></TABLE ></DIV ></BODY ></HTML >