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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-13 13:44:03 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-13 13:44:03 +0000 |
| commit | 293913568e6a7a86fd1479e1cff8e2ecb58d6568 (patch) | |
| tree | fc3b469a3ec5ab71b36ea97cc7aaddb838423a0c /doc/src/sgml/html/sql-copy.html | |
| parent | Initial commit. (diff) | |
| download | postgresql-16-293913568e6a7a86fd1479e1cff8e2ecb58d6568.tar.xz postgresql-16-293913568e6a7a86fd1479e1cff8e2ecb58d6568.zip | |
Adding upstream version 16.2.upstream/16.2
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'doc/src/sgml/html/sql-copy.html')
| -rw-r--r-- | doc/src/sgml/html/sql-copy.html | 648 |
1 files changed, 648 insertions, 0 deletions
diff --git a/doc/src/sgml/html/sql-copy.html b/doc/src/sgml/html/sql-copy.html new file mode 100644 index 0000000..88dcaf9 --- /dev/null +++ b/doc/src/sgml/html/sql-copy.html @@ -0,0 +1,648 @@ +<?xml version="1.0" encoding="UTF-8" standalone="no"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>COPY</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="sql-commit-prepared.html" title="COMMIT PREPARED" /><link rel="next" href="sql-create-access-method.html" title="CREATE ACCESS METHOD" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">COPY</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="sql-commit-prepared.html" title="COMMIT PREPARED">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="sql-commands.html" title="SQL Commands">Up</a></td><th width="60%" align="center">SQL Commands</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 16.2 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="sql-create-access-method.html" title="CREATE ACCESS METHOD">Next</a></td></tr></table><hr /></div><div class="refentry" id="SQL-COPY"><div class="titlepage"></div><a id="id-1.9.3.55.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle">COPY</span></h2><p>COPY — copy data between a file and a table</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis"> +COPY <em class="replaceable"><code>table_name</code></em> [ ( <em class="replaceable"><code>column_name</code></em> [, ...] ) ] + FROM { '<em class="replaceable"><code>filename</code></em>' | PROGRAM '<em class="replaceable"><code>command</code></em>' | STDIN } + [ [ WITH ] ( <em class="replaceable"><code>option</code></em> [, ...] ) ] + [ WHERE <em class="replaceable"><code>condition</code></em> ] + +COPY { <em class="replaceable"><code>table_name</code></em> [ ( <em class="replaceable"><code>column_name</code></em> [, ...] ) ] | ( <em class="replaceable"><code>query</code></em> ) } + TO { '<em class="replaceable"><code>filename</code></em>' | PROGRAM '<em class="replaceable"><code>command</code></em>' | STDOUT } + [ [ WITH ] ( <em class="replaceable"><code>option</code></em> [, ...] ) ] + +<span class="phrase">where <em class="replaceable"><code>option</code></em> can be one of:</span> + + FORMAT <em class="replaceable"><code>format_name</code></em> + FREEZE [ <em class="replaceable"><code>boolean</code></em> ] + DELIMITER '<em class="replaceable"><code>delimiter_character</code></em>' + NULL '<em class="replaceable"><code>null_string</code></em>' + DEFAULT '<em class="replaceable"><code>default_string</code></em>' + HEADER [ <em class="replaceable"><code>boolean</code></em> | MATCH ] + QUOTE '<em class="replaceable"><code>quote_character</code></em>' + ESCAPE '<em class="replaceable"><code>escape_character</code></em>' + FORCE_QUOTE { ( <em class="replaceable"><code>column_name</code></em> [, ...] ) | * } + FORCE_NOT_NULL ( <em class="replaceable"><code>column_name</code></em> [, ...] ) + FORCE_NULL ( <em class="replaceable"><code>column_name</code></em> [, ...] ) + ENCODING '<em class="replaceable"><code>encoding_name</code></em>' +</pre></div><div class="refsect1" id="id-1.9.3.55.5"><h2>Description</h2><p> + <code class="command">COPY</code> moves data between + <span class="productname">PostgreSQL</span> tables and standard file-system + files. <code class="command">COPY TO</code> copies the contents of a table + <span class="emphasis"><em>to</em></span> a file, while <code class="command">COPY FROM</code> copies + data <span class="emphasis"><em>from</em></span> a file to a table (appending the data to + whatever is in the table already). <code class="command">COPY TO</code> + can also copy the results of a <code class="command">SELECT</code> query. + </p><p> + If a column list is specified, <code class="command">COPY TO</code> copies only + the data in the specified columns to the file. For <code class="command">COPY + FROM</code>, each field in the file is inserted, in order, into the + specified column. Table columns not specified in the <code class="command">COPY + FROM</code> column list will receive their default values. + </p><p> + <code class="command">COPY</code> 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 by the + <span class="productname">PostgreSQL</span> user (the user ID the server + runs as) and the name must be specified from the viewpoint of the + server. When <code class="literal">PROGRAM</code> is specified, the server + executes the given command and reads from the standard output of the + program, or writes to the standard input of the program. The command + must be specified from the viewpoint of the server, and be executable + by the <span class="productname">PostgreSQL</span> user. When + <code class="literal">STDIN</code> or <code class="literal">STDOUT</code> is + specified, data is transmitted via the connection between the + client and the server. + </p><p> + Each backend running <code class="command">COPY</code> will report its progress + in the <code class="structname">pg_stat_progress_copy</code> view. See + <a class="xref" href="progress-reporting.html#COPY-PROGRESS-REPORTING" title="28.4.3. COPY Progress Reporting">Section 28.4.3</a> for details. + </p></div><div class="refsect1" id="id-1.9.3.55.6"><h2>Parameters</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="replaceable"><code>table_name</code></em></span></dt><dd><p> + The name (optionally schema-qualified) of an existing table. + </p></dd><dt><span class="term"><em class="replaceable"><code>column_name</code></em></span></dt><dd><p> + An optional list of columns to be copied. If no column list is + specified, all columns of the table except generated columns will be + copied. + </p></dd><dt><span class="term"><em class="replaceable"><code>query</code></em></span></dt><dd><p> + A <a class="link" href="sql-select.html" title="SELECT"><code class="command">SELECT</code></a>, + <a class="link" href="sql-values.html" title="VALUES"><code class="command">VALUES</code></a>, + <a class="link" href="sql-insert.html" title="INSERT"><code class="command">INSERT</code></a>, + <a class="link" href="sql-update.html" title="UPDATE"><code class="command">UPDATE</code></a>, or + <a class="link" href="sql-delete.html" title="DELETE"><code class="command">DELETE</code></a> command whose results are to be + copied. Note that parentheses are required around the query. + </p><p> + For <code class="command">INSERT</code>, <code class="command">UPDATE</code> and + <code class="command">DELETE</code> queries a <code class="literal">RETURNING</code> clause + must be provided, and the target relation must not have a conditional + rule, nor an <code class="literal">ALSO</code> rule, nor an + <code class="literal">INSTEAD</code> rule that expands to multiple statements. + </p></dd><dt><span class="term"><em class="replaceable"><code>filename</code></em></span></dt><dd><p> + The path name of the input or output file. An input file name can be + an absolute or relative path, but an output file name must be an absolute + path. Windows users might need to use an <code class="literal">E''</code> string and + double any backslashes used in the path name. + </p></dd><dt><span class="term"><code class="literal">PROGRAM</code></span></dt><dd><p> + A command to execute. In <code class="command">COPY FROM</code>, the input is + read from standard output of the command, and in <code class="command">COPY TO</code>, + the output is written to the standard input of the command. + </p><p> + Note that the command is invoked by the shell, so if you need to pass + any arguments that come from an untrusted source, you + must be careful to strip or escape any special characters that might + have a special meaning for the shell. For security reasons, it is best + to use a fixed command string, or at least avoid including any user input + in it. + </p></dd><dt><span class="term"><code class="literal">STDIN</code></span></dt><dd><p> + Specifies that input comes from the client application. + </p></dd><dt><span class="term"><code class="literal">STDOUT</code></span></dt><dd><p> + Specifies that output goes to the client application. + </p></dd><dt><span class="term"><em class="replaceable"><code>boolean</code></em></span></dt><dd><p> + Specifies whether the selected option should be turned on or off. + You can write <code class="literal">TRUE</code>, <code class="literal">ON</code>, or + <code class="literal">1</code> to enable the option, and <code class="literal">FALSE</code>, + <code class="literal">OFF</code>, or <code class="literal">0</code> to disable it. The + <em class="replaceable"><code>boolean</code></em> value can also + be omitted, in which case <code class="literal">TRUE</code> is assumed. + </p></dd><dt><span class="term"><code class="literal">FORMAT</code></span></dt><dd><p> + Selects the data format to be read or written: + <code class="literal">text</code>, + <code class="literal">csv</code> (Comma Separated Values), + or <code class="literal">binary</code>. + The default is <code class="literal">text</code>. + </p></dd><dt><span class="term"><code class="literal">FREEZE</code></span></dt><dd><p> + Requests copying the data with rows already frozen, just as they + would be after running the <code class="command">VACUUM FREEZE</code> command. + This is intended as a performance option for initial data loading. + Rows will be frozen only if the table being loaded has been created + or truncated in the current subtransaction, there are no cursors + open and there are no older snapshots held by this transaction. It is + currently not possible to perform a <code class="command">COPY FREEZE</code> on + a partitioned table. + </p><p> + Note that all other sessions will immediately be able to see the data + once it has been successfully loaded. This violates the normal rules + of MVCC visibility and users should be aware of the + potential problems this might cause. + </p></dd><dt><span class="term"><code class="literal">DELIMITER</code></span></dt><dd><p> + Specifies the character that separates columns within each row + (line) of the file. The default is a tab character in text format, + a comma in <code class="literal">CSV</code> format. + This must be a single one-byte character. + This option is not allowed when using <code class="literal">binary</code> format. + </p></dd><dt><span class="term"><code class="literal">NULL</code></span></dt><dd><p> + Specifies the string that represents a null value. The default is + <code class="literal">\N</code> (backslash-N) in text format, and an unquoted empty + string in <code class="literal">CSV</code> format. You might prefer an + empty string even in text format for cases where you don't want to + distinguish nulls from empty strings. + This option is not allowed when using <code class="literal">binary</code> format. + </p><div class="note"><h3 class="title">Note</h3><p> + When using <code class="command">COPY FROM</code>, 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 + <code class="command">COPY TO</code>. + </p></div></dd><dt><span class="term"><code class="literal">DEFAULT</code></span></dt><dd><p> + Specifies the string that represents a default value. Each time the string + is found in the input file, the default value of the corresponding column + will be used. + This option is allowed only in <code class="command">COPY FROM</code>, and only when + not using <code class="literal">binary</code> format. + </p></dd><dt><span class="term"><code class="literal">HEADER</code></span></dt><dd><p> + Specifies that the file contains a header line with the names of each + column in the file. On output, the first line contains the column + names from the table. On input, the first line is discarded when this + option is set to <code class="literal">true</code> (or equivalent Boolean value). + If this option is set to <code class="literal">MATCH</code>, the number and names + of the columns in the header line must match the actual column names of + the table, in order; otherwise an error is raised. + This option is not allowed when using <code class="literal">binary</code> format. + The <code class="literal">MATCH</code> option is only valid for <code class="command">COPY + FROM</code> commands. + </p></dd><dt><span class="term"><code class="literal">QUOTE</code></span></dt><dd><p> + Specifies the quoting character to be used when a data value is quoted. + The default is double-quote. + This must be a single one-byte character. + This option is allowed only when using <code class="literal">CSV</code> format. + </p></dd><dt><span class="term"><code class="literal">ESCAPE</code></span></dt><dd><p> + Specifies the character that should appear before a + data character that matches the <code class="literal">QUOTE</code> value. + The default is the same as the <code class="literal">QUOTE</code> value (so that + the quoting character is doubled if it appears in the data). + This must be a single one-byte character. + This option is allowed only when using <code class="literal">CSV</code> format. + </p></dd><dt><span class="term"><code class="literal">FORCE_QUOTE</code></span></dt><dd><p> + Forces quoting to be + used for all non-<code class="literal">NULL</code> values in each specified column. + <code class="literal">NULL</code> output is never quoted. If <code class="literal">*</code> is specified, + non-<code class="literal">NULL</code> values will be quoted in all columns. + This option is allowed only in <code class="command">COPY TO</code>, and only when + using <code class="literal">CSV</code> format. + </p></dd><dt><span class="term"><code class="literal">FORCE_NOT_NULL</code></span></dt><dd><p> + Do not match the specified columns' values against the null string. + In the default case where the null string is empty, this means that + empty values will be read as zero-length strings rather than nulls, + even when they are not quoted. + This option is allowed only in <code class="command">COPY FROM</code>, and only when + using <code class="literal">CSV</code> format. + </p></dd><dt><span class="term"><code class="literal">FORCE_NULL</code></span></dt><dd><p> + Match the specified columns' values against the null string, even + if it has been quoted, and if a match is found set the value to + <code class="literal">NULL</code>. In the default case where the null string is empty, + this converts a quoted empty string into NULL. + This option is allowed only in <code class="command">COPY FROM</code>, and only when + using <code class="literal">CSV</code> format. + </p></dd><dt><span class="term"><code class="literal">ENCODING</code></span></dt><dd><p> + Specifies that the file is encoded in the <em class="replaceable"><code>encoding_name</code></em>. If this option is + omitted, the current client encoding is used. See the Notes below + for more details. + </p></dd><dt><span class="term"><code class="literal">WHERE</code></span></dt><dd><p> + The optional <code class="literal">WHERE</code> clause has the general form +</p><pre class="synopsis"> +WHERE <em class="replaceable"><code>condition</code></em> +</pre><p> + where <em class="replaceable"><code>condition</code></em> is + any expression that evaluates to a result of type + <code class="type">boolean</code>. Any row that does not satisfy this + condition will not be inserted to the table. A row satisfies the + condition if it returns true when the actual row values are + substituted for any variable references. + </p><p> + Currently, subqueries are not allowed in <code class="literal">WHERE</code> + expressions, and the evaluation does not see any changes made by the + <code class="command">COPY</code> itself (this matters when the expression + contains calls to <code class="literal">VOLATILE</code> functions). + </p></dd></dl></div></div><div class="refsect1" id="id-1.9.3.55.7"><h2>Outputs</h2><p> + On successful completion, a <code class="command">COPY</code> command returns a command + tag of the form +</p><pre class="screen"> +COPY <em class="replaceable"><code>count</code></em> +</pre><p> + The <em class="replaceable"><code>count</code></em> is the number + of rows copied. + </p><div class="note"><h3 class="title">Note</h3><p> + <span class="application">psql</span> will print this command tag only if the command + was not <code class="literal">COPY ... TO STDOUT</code>, or the + equivalent <span class="application">psql</span> meta-command + <code class="literal">\copy ... to stdout</code>. This is to prevent confusing the + command tag with the data that was just printed. + </p></div></div><div class="refsect1" id="id-1.9.3.55.8"><h2>Notes</h2><p> + <code class="command">COPY TO</code> can be used only with plain + tables, not views, and does not copy rows from child tables + or child partitions. For example, <code class="literal">COPY <em class="replaceable"><code>table</code></em> TO</code> copies + the same rows as <code class="literal">SELECT * FROM ONLY <em class="replaceable"><code>table</code></em></code>. + The syntax <code class="literal">COPY (SELECT * FROM <em class="replaceable"><code>table</code></em>) TO ...</code> can be used to + dump all of the rows in an inheritance hierarchy, partitioned table, + or view. + </p><p> + <code class="command">COPY FROM</code> can be used with plain, foreign, or + partitioned tables or with views that have + <code class="literal">INSTEAD OF INSERT</code> triggers. + </p><p> + You must have select privilege on the table + whose values are read by <code class="command">COPY TO</code>, and + insert privilege on the table into which values + are inserted by <code class="command">COPY FROM</code>. It is sufficient + to have column privileges on the column(s) listed in the command. + </p><p> + If row-level security is enabled for the table, the relevant + <code class="command">SELECT</code> policies will apply to <code class="literal">COPY + <em class="replaceable"><code>table</code></em> TO</code> statements. + Currently, <code class="command">COPY FROM</code> is not supported for tables + with row-level security. Use equivalent <code class="command">INSERT</code> + statements instead. + </p><p> + Files named in a <code class="command">COPY</code> 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. Similarly, + the command specified with <code class="literal">PROGRAM</code> is executed directly + by the server, not by the client application, must be executable by the + <span class="productname">PostgreSQL</span> user. + <code class="command">COPY</code> naming a file or command is only allowed to + database superusers or users who are granted one of the roles + <code class="literal">pg_read_server_files</code>, + <code class="literal">pg_write_server_files</code>, + or <code class="literal">pg_execute_server_program</code>, since it allows reading + or writing any file or running a program that the server has privileges to + access. + </p><p> + Do not confuse <code class="command">COPY</code> with the + <span class="application">psql</span> instruction + <code class="command"><a class="link" href="app-psql.html#APP-PSQL-META-COMMANDS-COPY">\copy</a></code>. <code class="command">\copy</code> invokes + <code class="command">COPY FROM STDIN</code> or <code class="command">COPY TO + STDOUT</code>, 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 <code class="command">\copy</code> is used. + </p><p> + It is recommended that the file name used in <code class="command">COPY</code> + always be specified as an absolute path. This is enforced by the + server in the case of <code class="command">COPY TO</code>, but for + <code class="command">COPY FROM</code> 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 (normally + the cluster's data directory), not the client's working directory. + </p><p> + Executing a command with <code class="literal">PROGRAM</code> might be restricted + by the operating system's access control mechanisms, such as SELinux. + </p><p> + <code class="command">COPY FROM</code> will invoke any triggers and check + constraints on the destination table. However, it will not invoke rules. + </p><p> + For identity columns, the <code class="command">COPY FROM</code> command will always + write the column values provided in the input data, like + the <code class="command">INSERT</code> option <code class="literal">OVERRIDING SYSTEM + VALUE</code>. + </p><p> + <code class="command">COPY</code> input and output is affected by + <code class="varname">DateStyle</code>. To ensure portability to other + <span class="productname">PostgreSQL</span> installations that might use + non-default <code class="varname">DateStyle</code> settings, + <code class="varname">DateStyle</code> should be set to <code class="literal">ISO</code> before + using <code class="command">COPY TO</code>. It is also a good idea to avoid dumping + data with <code class="varname">IntervalStyle</code> set to + <code class="literal">sql_standard</code>, because negative interval values might be + misinterpreted by a server that has a different setting for + <code class="varname">IntervalStyle</code>. + </p><p> + Input data is interpreted according to <code class="literal">ENCODING</code> + option or the current client encoding, and output data is encoded + in <code class="literal">ENCODING</code> or the current client encoding, even + if the data does not pass through the client but is read from or + written to a file directly by the server. + </p><p> + <code class="command">COPY</code> stops operation at the first error. This + should not lead to problems in the event of a <code class="command">COPY + TO</code>, but the target table will already have received + earlier rows in a <code class="command">COPY FROM</code>. These rows will not + be visible or accessible, but they still occupy disk space. This might + amount to a considerable amount of wasted disk space if the failure + happened well into a large copy operation. You might wish to invoke + <code class="command">VACUUM</code> to recover the wasted space. + </p><p> + <code class="literal">FORCE_NULL</code> and <code class="literal">FORCE_NOT_NULL</code> can be used + simultaneously on the same column. This results in converting quoted + null strings to null values and unquoted null strings to empty strings. + </p></div><div class="refsect1" id="id-1.9.3.55.9"><h2>File Formats</h2><div class="refsect2" id="id-1.9.3.55.9.2"><h3>Text Format</h3><p> + When the <code class="literal">text</code> format is used, + 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. + <code class="command">COPY FROM</code> will raise an error if any line of the + input file contains more or fewer columns than are expected. + </p><p> + End of data can be represented by a single line containing just + backslash-period (<code class="literal">\.</code>). 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 (<code class="literal">\</code>) can be used in the + <code class="command">COPY</code> data to quote data characters that might + otherwise be taken as row or column delimiters. In particular, the + following characters <span class="emphasis"><em>must</em></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 <code class="command">COPY TO</code> without + adding any backslashes; conversely, <code class="command">COPY FROM</code> matches + the input against the null string before removing backslashes. Therefore, + a null string such as <code class="literal">\N</code> cannot be confused with + the actual data value <code class="literal">\N</code> (which would be represented + as <code class="literal">\\N</code>). + </p><p> + The following special backslash sequences are recognized by + <code class="command">COPY FROM</code>: + + </p><div class="informaltable"><table class="informaltable" border="1"><colgroup><col /><col /></colgroup><thead><tr><th>Sequence</th><th>Represents</th></tr></thead><tbody><tr><td><code class="literal">\b</code></td><td>Backspace (ASCII 8)</td></tr><tr><td><code class="literal">\f</code></td><td>Form feed (ASCII 12)</td></tr><tr><td><code class="literal">\n</code></td><td>Newline (ASCII 10)</td></tr><tr><td><code class="literal">\r</code></td><td>Carriage return (ASCII 13)</td></tr><tr><td><code class="literal">\t</code></td><td>Tab (ASCII 9)</td></tr><tr><td><code class="literal">\v</code></td><td>Vertical tab (ASCII 11)</td></tr><tr><td><code class="literal">\</code><em class="replaceable"><code>digits</code></em></td><td>Backslash followed by one to three octal digits specifies + the byte with that numeric code</td></tr><tr><td><code class="literal">\x</code><em class="replaceable"><code>digits</code></em></td><td>Backslash <code class="literal">x</code> followed by one or two hex digits specifies + the byte with that numeric code</td></tr></tbody></table></div><p> + + Presently, <code class="command">COPY TO</code> will never emit an octal or + hex-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 (<code class="literal">\.</code>) or the null string (<code class="literal">\N</code> by + default). These strings will be recognized before any other backslash + processing is done. + </p><p> + It is strongly recommended that applications generating <code class="command">COPY</code> data convert + data newlines and carriage returns to the <code class="literal">\n</code> and + <code class="literal">\r</code> 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 <code class="command">COPY</code> file is + transferred across different machines (for example, from Unix to Windows + or vice versa). + </p><p> + All backslash sequences are interpreted after encoding conversion. + The bytes specified with the octal and hex-digit backslash sequences must + form valid characters in the database encoding. + </p><p> + <code class="command">COPY TO</code> will terminate each row with a Unix-style + newline (<span class="quote">“<span class="quote"><code class="literal">\n</code></span>”</span>). Servers running on Microsoft Windows instead + output carriage return/newline (<span class="quote">“<span class="quote"><code class="literal">\r\n</code></span>”</span>), but only for + <code class="command">COPY</code> to a server file; for consistency across platforms, + <code class="command">COPY TO STDOUT</code> always sends <span class="quote">“<span class="quote"><code class="literal">\n</code></span>”</span> + regardless of server platform. + <code class="command">COPY FROM</code> 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, <code class="command">COPY FROM</code> will complain if the line + endings in the input are not all alike. + </p></div><div class="refsect2" id="id-1.9.3.55.9.3"><h3>CSV Format</h3><p> + This format option is used for importing and exporting the Comma + Separated Value (<code class="literal">CSV</code>) file format used by many other + programs, such as spreadsheets. Instead of the escaping rules used by + <span class="productname">PostgreSQL</span>'s standard text format, it + produces and recognizes the common <code class="literal">CSV</code> escaping mechanism. + </p><p> + The values in each record are separated by the <code class="literal">DELIMITER</code> + character. If the value contains the delimiter character, the + <code class="literal">QUOTE</code> character, the <code class="literal">NULL</code> string, a carriage + return, or line feed character, then the whole value is prefixed and + suffixed by the <code class="literal">QUOTE</code> character, and any occurrence + within the value of a <code class="literal">QUOTE</code> character or the + <code class="literal">ESCAPE</code> character is preceded by the escape character. + You can also use <code class="literal">FORCE_QUOTE</code> to force quotes when outputting + non-<code class="literal">NULL</code> values in specific columns. + </p><p> + The <code class="literal">CSV</code> format has no standard way to distinguish a + <code class="literal">NULL</code> value from an empty string. + <span class="productname">PostgreSQL</span>'s <code class="command">COPY</code> handles this by quoting. + A <code class="literal">NULL</code> is output as the <code class="literal">NULL</code> parameter string + and is not quoted, while a non-<code class="literal">NULL</code> value matching the + <code class="literal">NULL</code> parameter string is quoted. For example, with the + default settings, a <code class="literal">NULL</code> is written as an unquoted empty + string, while an empty string data value is written with double quotes + (<code class="literal">""</code>). Reading values follows similar rules. You can + use <code class="literal">FORCE_NOT_NULL</code> to prevent <code class="literal">NULL</code> input + comparisons for specific columns. You can also use + <code class="literal">FORCE_NULL</code> to convert quoted null string data values to + <code class="literal">NULL</code>. + </p><p> + Because backslash is not a special character in the <code class="literal">CSV</code> + format, <code class="literal">\.</code>, the end-of-data marker, could also appear + as a data value. To avoid any misinterpretation, a <code class="literal">\.</code> + data value appearing as a lone entry on a line is automatically + quoted on output, and on input, if quoted, is not interpreted as the + end-of-data marker. If you are loading a file created by another + application that has a single unquoted column and might have a + value of <code class="literal">\.</code>, you might need to quote that value in the + input file. + </p><div class="note"><h3 class="title">Note</h3><p> + In <code class="literal">CSV</code> format, all characters are significant. A quoted value + surrounded by white space, or any characters other than + <code class="literal">DELIMITER</code>, will include those characters. This can cause + errors if you import data from a system that pads <code class="literal">CSV</code> + lines with white space out to some fixed width. If such a situation + arises you might need to preprocess the <code class="literal">CSV</code> file to remove + the trailing white space, before importing the data into + <span class="productname">PostgreSQL</span>. + </p></div><div class="note"><h3 class="title">Note</h3><p> + <code class="literal">CSV</code> format will both recognize and produce <code class="literal">CSV</code> files with quoted + values containing embedded carriage returns and line feeds. Thus + the files are not strictly one line per table row like text-format + files. + </p></div><div class="note"><h3 class="title">Note</h3><p> + Many programs produce strange and occasionally perverse <code class="literal">CSV</code> 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 <code class="command">COPY</code> might produce files that other + programs cannot process. + </p></div></div><div class="refsect2" id="id-1.9.3.55.9.4"><h3>Binary Format</h3><p> + The <code class="literal">binary</code> format option causes all data to be + stored/read as binary format rather than as text. It is + somewhat faster than the text and <code class="literal">CSV</code> formats, + but a binary-format file is less portable across machine architectures and + <span class="productname">PostgreSQL</span> versions. + Also, the binary format is very data type specific; for example + it will not work to output binary data from a <code class="type">smallint</code> column + and read it into an <code class="type">integer</code> column, even though that would work + fine in text format. + </p><p> + The <code class="literal">binary</code> file format consists + of a file header, zero or more tuples containing the row data, and + a file trailer. Headers and data are in network byte order. + </p><div class="note"><h3 class="title">Note</h3><p> + <span class="productname">PostgreSQL</span> releases before 7.4 used a + different binary file format. + </p></div><div class="refsect3" id="id-1.9.3.55.9.4.5"><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><div class="variablelist"><dl class="variablelist"><dt><span class="term">Signature</span></dt><dd><p> +11-byte sequence <code class="literal">PGCOPY\n\377\r\n\0</code> — 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><span class="term">Flags field</span></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><div class="variablelist"><dl class="variablelist"><dt><span class="term">Bit 16</span></dt><dd><p> + If 1, OIDs are included in the data; if 0, not. Oid system columns + are not supported in <span class="productname">PostgreSQL</span> + anymore, but the format still contains the indicator. + </p></dd></dl></div></dd><dt><span class="term">Header extension area length</span></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" id="id-1.9.3.55.9.4.6"><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 binary-format file are +assumed to be in binary format (format code one). It is anticipated that a +future extension might 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 +<code class="filename">src/backend/utils/adt/</code> 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. Note that oid system columns are not supported in current +versions of <span class="productname">PostgreSQL</span>. + </p></div><div class="refsect3" id="id-1.9.3.55.9.4.7"><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" id="id-1.9.3.55.10"><h2>Examples</h2><p> + The following example copies a table to the client + using the vertical bar (<code class="literal">|</code>) as the field delimiter: +</p><pre class="programlisting"> +COPY country TO STDOUT (DELIMITER '|'); +</pre><p> + </p><p> + To copy data from a file into the <code class="literal">country</code> table: +</p><pre class="programlisting"> +COPY country FROM '/usr1/proj/bray/sql/country_data'; +</pre><p> + </p><p> + To copy into a file just the countries whose names start with 'A': +</p><pre class="programlisting"> +COPY (SELECT * FROM country WHERE country_name LIKE 'A%') TO '/usr1/proj/bray/sql/a_list_countries.copy'; +</pre><p> + </p><p> + To copy into a compressed file, you can pipe the output through an external + compression program: +</p><pre class="programlisting"> +COPY country TO PROGRAM 'gzip > /usr1/proj/bray/sql/country_data.gz'; +</pre><p> + </p><p> + Here is a sample of data suitable for copying into a table from + <code class="literal">STDIN</code>: +</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 <code class="command">od -c</code>. The table has three columns; + the first has type <code class="type">char(2)</code>, the second has type <code class="type">text</code>, + and the third has type <code class="type">integer</code>. 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></div><div class="refsect1" id="id-1.9.3.55.11"><h2>Compatibility</h2><p> + There is no <code class="command">COPY</code> statement in the SQL standard. + </p><p> + The following syntax was used before <span class="productname">PostgreSQL</span> + version 9.0 and is still supported: + +</p><pre class="synopsis"> +COPY <em class="replaceable"><code>table_name</code></em> [ ( <em class="replaceable"><code>column_name</code></em> [, ...] ) ] + FROM { '<em class="replaceable"><code>filename</code></em>' | STDIN } + [ [ WITH ] + [ BINARY ] + [ DELIMITER [ AS ] '<em class="replaceable"><code>delimiter_character</code></em>' ] + [ NULL [ AS ] '<em class="replaceable"><code>null_string</code></em>' ] + [ CSV [ HEADER ] + [ QUOTE [ AS ] '<em class="replaceable"><code>quote_character</code></em>' ] + [ ESCAPE [ AS ] '<em class="replaceable"><code>escape_character</code></em>' ] + [ FORCE NOT NULL <em class="replaceable"><code>column_name</code></em> [, ...] ] ] ] + +COPY { <em class="replaceable"><code>table_name</code></em> [ ( <em class="replaceable"><code>column_name</code></em> [, ...] ) ] | ( <em class="replaceable"><code>query</code></em> ) } + TO { '<em class="replaceable"><code>filename</code></em>' | STDOUT } + [ [ WITH ] + [ BINARY ] + [ DELIMITER [ AS ] '<em class="replaceable"><code>delimiter_character</code></em>' ] + [ NULL [ AS ] '<em class="replaceable"><code>null_string</code></em>' ] + [ CSV [ HEADER ] + [ QUOTE [ AS ] '<em class="replaceable"><code>quote_character</code></em>' ] + [ ESCAPE [ AS ] '<em class="replaceable"><code>escape_character</code></em>' ] + [ FORCE QUOTE { <em class="replaceable"><code>column_name</code></em> [, ...] | * } ] ] ] +</pre><p> + + Note that in this syntax, <code class="literal">BINARY</code> and <code class="literal">CSV</code> are + treated as independent keywords, not as arguments of a <code class="literal">FORMAT</code> + option. + </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 ] <em class="replaceable"><code>table_name</code></em> + FROM { '<em class="replaceable"><code>filename</code></em>' | STDIN } + [ [USING] DELIMITERS '<em class="replaceable"><code>delimiter_character</code></em>' ] + [ WITH NULL AS '<em class="replaceable"><code>null_string</code></em>' ] + +COPY [ BINARY ] <em class="replaceable"><code>table_name</code></em> + TO { '<em class="replaceable"><code>filename</code></em>' | STDOUT } + [ [USING] DELIMITERS '<em class="replaceable"><code>delimiter_character</code></em>' ] + [ WITH NULL AS '<em class="replaceable"><code>null_string</code></em>' ] +</pre></div><div class="refsect1" id="id-1.9.3.55.12"><h2>See Also</h2><span class="simplelist"><a class="xref" href="progress-reporting.html#COPY-PROGRESS-REPORTING" title="28.4.3. 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