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Diffstat (limited to 'doc/src/sgml/ref/copy.sgml')
| -rw-r--r-- | doc/src/sgml/ref/copy.sgml | 279 |
1 files changed, 160 insertions, 119 deletions
diff --git a/doc/src/sgml/ref/copy.sgml b/doc/src/sgml/ref/copy.sgml index 216d2abf1e..174fd26078 100644 --- a/doc/src/sgml/ref/copy.sgml +++ b/doc/src/sgml/ref/copy.sgml @@ -14,69 +14,112 @@ </REFPURPOSE> <REFSYNOPSISDIV> <REFSYNOPSISDIVINFO> - <DATE>1998-04-15</DATE> + <DATE>1998-09-08</DATE> </REFSYNOPSISDIVINFO> <SYNOPSIS> - COPY [BINARY] <replaceable class="parameter">table</replaceable> [WITH OIDS] - TO|FROM '<replaceable class="parameter">filename</replaceable>'|stdin|stdout - [USING DELIMITERS '<replaceable class="parameter">delimiter</replaceable>'] +COPY [ BINARY ] <replaceable class="parameter">table</replaceable> [ WITH OIDS ] + FROM { '<replaceable class="parameter">filename</replaceable>' | <filename>stdin</filename> } + [ USING DELIMITERS '<replaceable class="parameter">delimiter</replaceable>' ] +COPY [ BINARY ] <replaceable class="parameter">table</replaceable> [ WITH OIDS ] + TO { '<replaceable class="parameter">filename</replaceable>' | <filename>stdout</filename> } + [ USING DELIMITERS '<replaceable class="parameter">delimiter</replaceable>' ] </SYNOPSIS> <REFSECT2 ID="R2-SQL-COPY-1"> <REFSECT2INFO> - <DATE>1998-04-15</DATE> + <DATE>1998-09-08</DATE> </REFSECT2INFO> <TITLE> Inputs </TITLE> <PARA> - </PARA> - <VARIABLELIST> - <VARLISTENTRY> - <TERM> - </TERM> - <LISTITEM> - <PARA> <VARIABLELIST> <VARLISTENTRY> <TERM> - <ReturnValue><replaceable class="parameter">table</replaceable></ReturnValue> +BINARY </TERM> <LISTITEM> <PARA> - The name of a table. + Changes the behavior of field formatting, forcing all data to be + stored or read as binary objects rather than as text. </PARA> </LISTITEM> </VARLISTENTRY> <VARLISTENTRY> <TERM> - <ReturnValue><replaceable class="parameter">delimiter</replaceable></ReturnValue> +<replaceable class="parameter">table</replaceable> </TERM> <LISTITEM> <PARA> - A character that delimits fields. +The name of an existing table. + </PARA> + </LISTITEM> + </VARLISTENTRY> + <VARLISTENTRY> + <TERM> +WITH OIDS + </TERM> + <LISTITEM> + <PARA> +Copies the internal unique object id (OID) for each row. + </PARA> + </LISTITEM> + </VARLISTENTRY> + <VARLISTENTRY> + <TERM> +<replaceable class="parameter">filename</replaceable> + </TERM> + <LISTITEM> + <PARA> +The absolute Unix pathname of the input or output file. + </PARA> + </LISTITEM> + </VARLISTENTRY> + <VARLISTENTRY> + <TERM> +<filename>stdin</filename> + </TERM> + <LISTITEM> + <PARA> +Specifies that input comes from a pipe or terminal. + </PARA> + </LISTITEM> + </VARLISTENTRY> + <VARLISTENTRY> + <TERM> +<filename>stdout</filename> + </TERM> + <LISTITEM> + <PARA> +Specifies that output goes to a pipe or terminal. + </PARA> + </LISTITEM> + </VARLISTENTRY> + <VARLISTENTRY> + <TERM> + <replaceable class="parameter">delimiter</replaceable> + </TERM> + <LISTITEM> + <PARA> + A character that delimits the input or output fields. </PARA> </LISTITEM> </VARLISTENTRY> </variablelist> - </LISTITEM> - </VARLISTENTRY> - </VARIABLELIST> </REFSECT2> <REFSECT2 ID="R2-SQL-COPY-2"> <REFSECT2INFO> - <DATE>1998-04-15</DATE> + <DATE>1998-09-08</DATE> </REFSECT2INFO> <TITLE> Outputs </TITLE> <PARA> - </PARA> <VARIABLELIST> <VARLISTENTRY> <TERM> - Status + <Replaceable>status</Replaceable> </TERM> <LISTITEM> <PARA> @@ -110,84 +153,82 @@ <REFSECT1 ID="R1-SQL-COPY-1"> <REFSECT1INFO> - <DATE>1998-04-15</DATE> + <DATE>1998-09-08</DATE> </REFSECT1INFO> <TITLE> Description </TITLE> <PARA> - <command>COPY</command> moves data between PostgreSQL tables and - standard Unix files. The keyword <function>BINARY</function> - changes the behavior of field formatting, as described - below. <replaceable class="parameter">Table</replaceable> is the - name of an existing table. The keyword <function>WITH - OIDS</function> copies the internal unique object id (OID) for each - row. <replaceable class="parameter">Filename</replaceable> is the - absolute Unix pathname of the file. In place of a filename, the - keywords <function>stdin</function> and <function>stdout</function> - can be used, so that input to <command>COPY</command> can be written - by a libpq application and output from <command>COPY</command> can - be read by a libpq application. - </para> + <command>COPY</command> moves data between + <productname>Postgres</productname> tables and + standard Unix files. + +<para> +<command>COPY</command> instructs + the <productname>Postgres</productname> backend +to directly read from or write to a file. The file must be directly visible to +the backend and the name must be specified from the viewpoint of the backend. +If <filename>stdin</filename> or <filename>stdout</filename> are specified, data flows through the client frontend to +the backend. + + <REFSECT2 ID="R2-SQL-COPY-3"> + <REFSECT2INFO> + <DATE>1998-09-08</DATE> + </REFSECT2INFO> + <TITLE> + Notes + </TITLE> <para> - The <function>BINARY</function> keyword will force all data to be - stored/read as binary objects rather than as ASCII text. It is + The BINARY keyword will force all data to be + stored/read as binary objects rather than as text. It is somewhat faster than the normal copy command, but is not generally portable, and the files generated are somewhat larger, although this factor is highly dependent on the data itself. By - default, an ASCII copy uses a tab (\t) character as a delimiter. + default, a text copy uses a tab ("\t") character as a delimiter. The delimiter may also be changed to any other single character - with the keyword <function>USING DELIMITERS</function>. Characters + with the keyword phrase USING DELIMITERS. Characters in data fields which happen to match the delimiter character will be quoted. </para> - <REFSECT2 ID="R2-SQL-COPY-3"> - <REFSECT2INFO> - <DATE>1998-04-15</DATE> - </REFSECT2INFO> - <TITLE> - Notes - </TITLE> <para> You must have select access on any table whose values are read by <command>COPY</command>, and either insert or update access to a table into which values are being inserted by <command>COPY</command>. The backend also needs appropriate Unix permissions for any file read or written by <command>COPY</command>. -<comment> -Is this right? The man page talked of read, write and append access, which -is neither SQL nor Unix terminology. -</comment> </para> <para> - The keyword <function>USING DELIMITERS</function> is inaptly - named, since only a single character may be specified. (If a - group of characters is specified, only the first character is - used.) - </para> - <para> - WARNING: do not confuse <command>COPY</command> with the - <command>psql</command> instruction <command>\copy</command>. - </para> + The keyword phrase USING DELIMITERS specifies a single character +to be used for all delimiters between columns. If multiple characters +are specified in the delimiter string, only the first character is + used. + + <tip> +<para> + Do not confuse <command>COPY</command> with the + <application>psql</application> instruction <command>\copy</command>. +</tip> + </REFSECT2> </refsect1> + <refsect1 ID="R1-SQL-COPY-2"> <refsect1info> <date>1998-05-04</date> </refsect1info> - <title>Format of output files</title> + <title>File Formats</title> <refsect2> <refsect2info> <date>1998-05-04</date> </refsect2info> - <title>ASCII copy format</title> + <title>Text Format</title> <para> - When <command>COPY</command> is used without <function>BINARY</function>, - the file generated will have each instance on a single line, with each - attribute separated by the delimiter character. Embedded + When <command>COPY TO</command> is used without the BINARY option, + the file generated will have each row (instance) on a single line, with each + column (attribute) separated by the delimiter character. Embedded delimiter characters will be preceded by a backslash character - (\). The attribute values themselves are strings generated by the + ("\"). The attribute values themselves are strings generated by the output function associated with each attribute type. The output function for a type should not try to generate the backslash character; this will be handled by <command>COPY</command> itself. @@ -195,29 +236,31 @@ is neither SQL nor Unix terminology. <para> The actual format for each instance is <programlisting> - <attr1><<replaceable class=parameter>separator</replaceable>><attr2><<replaceable class=parameter>separator</replaceable>>...<<replaceable class=parameter>separator</replaceable>><attr<replaceable class="parameter">n</replaceable>><newline></programlisting> +<attr1><<replaceable class=parameter>separator</replaceable>><attr2><<replaceable class=parameter>separator</replaceable>>...<<replaceable class=parameter>separator</replaceable>><attr<replaceable class="parameter">n</replaceable>><newline> +</programlisting> The oid is placed on the beginning of the line - if <function>WITH OIDS</function> is specified. + if WITH OIDS is specified. </para> <para> If <command>COPY</command> is sending its output to standard - output instead of a file, it will send a backslash(\) and a period - (.) followed immediately by a newline, on a separate line, + output instead of a file, it will send a backslash("\") and a period + (".") followed immediately by a newline, on a separate line, when it is done. Similarly, if <command>COPY</command> is reading - from standard input, it will expect a backslash (\) and a period - (.) followed by a newline, as the first three characters on a - line, to denote end-of-file. However, <command>COPY</command> + from standard input, it will expect a backslash ("\") and a period + (".") followed by a newline, as the first three characters on a + line to denote end-of-file. However, <command>COPY</command> will terminate (followed by the backend itself) if a true EOF is - encountered. + encountered before this special end-of-file pattern is found. </para> <para> - The backslash character has special meaning. NULL attributes are - output as \N. A literal backslash character is output as two - consecutive backslashes. A literal tab character is represented + The backslash character has other special meanings. NULL attributes are + output as "\N". A literal backslash character is output as two + consecutive backslashes ("\\"). A literal tab character is represented as a backslash and a tab. A literal newline character is - represented as a backslash and a newline. When loading ASCII data - not generated by PostgreSQL, you will need to convert backslash - characters (\) to double-backslashes (\\) to ensure that they are loaded + represented as a backslash and a newline. When loading text data + not generated by <acronym>Postgres</acronym>, + you will need to convert backslash + characters ("\") to double-backslashes ("\\") to ensure that they are loaded properly. </para> </refsect2> @@ -225,7 +268,7 @@ is neither SQL nor Unix terminology. <refsect2info> <date>1998-05-04</date> </refsect2info> - <title>Binary copy format</title> + <title>Binary Format</title> <para> In the case of <command>COPY BINARY</command>, the first four bytes in the file will be the number of instances in the file. If @@ -270,16 +313,8 @@ is neither SQL nor Unix terminology. <entry>number of null attributes</entry> </row> <row> - <entry>[uint32</entry> - <entry>attribute number of first null attribute, counting from 0</entry> - </row> - <row> - <entry>...</entry> - <entry>...</entry> - </row> - <row> - <entry>uint32</entry> - <entry>attribute number of last null attribute]</entry> + <entry>[uint32,...,uint32]</entry> + <entry>attribute numbers of attributes, counting from 0</entry> </row> <row> <entry>-</entry> @@ -294,12 +329,12 @@ is neither SQL nor Unix terminology. <refsect2info> <date>1998-05-04</date> </refsect2info> - <title>Alignment of binary data</title> + <title>Alignment of Binary Data</title> <para> On Sun-3s, 2-byte attributes are aligned on two-byte boundaries, and all larger attributes are aligned on four-byte boundaries. Character attributes are aligned on single-byte boundaries. On - other machines, all attributes larger than 1 byte are aligned on + most other machines, all attributes larger than 1 byte are aligned on four-byte boundaries. Note that variable length attributes are preceded by the attribute's length; arrays are simply contiguous streams of the array element type. @@ -313,19 +348,22 @@ is neither SQL nor Unix terminology. Usage </TITLE> <PARA> -To copy a table to standard output, using | as a delimiter +The following example copies a table to standard output, + using a vertical bar ("|") as the field + delimiter: </PARA> <ProgramListing> - COPY country TO stdout USING DELIMITERS '|'; +COPY country TO <filename>stdout</filename> USING DELIMITERS '|'; </ProgramListing> <PARA> - To copy data from a Unix file into a table: + To copy data from a Unix file into a table "country": </PARA> <ProgramListing> - COPY country FROM '/usr1/proj/bray/sql/country_data'; +COPY country FROM '/usr1/proj/bray/sql/country_data'; </ProgramListing> <PARA> - A sample of data suitable for copying into a table from <filename>stdin</filename> (so it + Here is a sample of data suitable for copying into a table + from <filename>stdin</filename> (so it has the termination sequence on the last line): </PARA> <ProgramListing> @@ -338,10 +376,13 @@ has the termination sequence on the last line): \. </ProgramListing> <PARA> - The same data, output in binary format on a Linux Intel machine. - The data is shown after filtering through the Unix utility <command>od -c</command>. The table has - three fields; the first is <classname>char(2)</classname> and the second is <classname>text</classname>. All the - rows have a null value in the third field). Notice how the <classname>char(2)</classname> + The same data, output in binary format on a Linux/i586 machine. + The data is shown after filtering through + the Unix utility <command>od -c</command>. The table has + three fields; the first is <classname>char(2)</classname> + and the second is <classname>text</classname>. All the + rows have a null value in the third field. + Notice how the <classname>char(2)</classname> field is padded with nulls to four bytes and the text field is preceded by its length: </PARA> @@ -359,32 +400,32 @@ has the termination sequence on the last line): </ProgramListing> </refsect1> - <refsect1 ID="R1-SQL-COPY-4"> - <title>See also</title> - <para> - insert(l), create table(l), vacuum(l), libpq. - </para> - </refsect1> - <refsect1 ID="R1-SQL-COPY-5"> <title>Bugs</title> <para> <command>COPY</command> stops operation at the first error. This - should not lead to problems in the event of a copy from, but the - target relation will, of course, be partially modified in a copy - to. The <command>VACUUM</command> query should be used to clean up + should not lead to problems in the event of + a <command>COPY FROM</command>, but the + target relation will, of course, be partially modified in a +<command>COPY TO</command>. + The <command>VACUUM</command> query should be used to clean up after a failed copy. </para> <para> - Because Postgres' current directory is not the same as the user's - working directory, the result of copying to a file "foo" (without + Because the Postgres backend's current working directory + is not usually the same as the user's + working directory, the result of copying to a file + "<filename>foo</filename>" (without additional path information) may yield unexpected results for the - naive user. In this case, "foo" will wind up in $PGDATA/foo. In - general, the full pathname should be used when specifying files to + naive user. In this case, <filename>foo</filename> + will wind up in <filename>$PGDATA/foo</filename>. In + general, the full pathname as it would appear to the backend server machine +should be used when specifying files to be copied. </para> <para> - Files used as arguments to the copy command must reside on or be + Files used as arguments to <command>COPY</command> +must reside on or be accessible to the database server machine by being either on local disks or on a networked file system. </para> @@ -405,13 +446,13 @@ has the termination sequence on the last line): <REFSECT2 ID="R2-SQL-COPY-4"> <REFSECT2INFO> - <DATE>1998-04-15</DATE> + <DATE>1998-09-08</DATE> </REFSECT2INFO> <TITLE> SQL92 </TITLE> <PARA> - There is no COPY statement in SQL92. + There is no <command>COPY</command> statement in SQL92. </PARA> </refsect2> </refsect1> |