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Diffstat (limited to 'doc/src/sgml/ref/create_sequence.sgml')
| -rw-r--r-- | doc/src/sgml/ref/create_sequence.sgml | 497 |
1 files changed, 242 insertions, 255 deletions
diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml index f6d6ae0b8d4..352c839f917 100644 --- a/doc/src/sgml/ref/create_sequence.sgml +++ b/doc/src/sgml/ref/create_sequence.sgml @@ -1,23 +1,23 @@ -<REFENTRY ID="SQL-CREATESEQUENCE"> - <REFMETA> - <REFENTRYTITLE> +<refentry id="SQL-CREATESEQUENCE"> + <refmeta> + <refentrytitle> CREATE SEQUENCE - </REFENTRYTITLE> - <REFMISCINFO>SQL - Language Statements</REFMISCINFO> - </REFMETA> - <REFNAMEDIV> - <REFNAME> + </refentrytitle> + <refmiscinfo>SQL - Language Statements</refmiscinfo> + </refmeta> + <refnamediv> + <refname> CREATE SEQUENCE - </REFNAME> - <REFPURPOSE> + </refname> + <refpurpose> Creates a new sequence number generator - </REFPURPOSE> + </refpurpose> </refnamediv> - <REFSYNOPSISDIV> - <REFSYNOPSISDIVINFO> - <DATE>1998-04-15</DATE> - </REFSYNOPSISDIVINFO> - <SYNOPSIS> + <refsynopsisdiv> + <refsynopsisdivinfo> + <date>1998-04-15</date> + </refsynopsisdivinfo> + <synopsis> CREATE SEQUENCE <replaceable class="parameter">seqname</replaceable> [ INCREMENT <replaceable class="parameter">increment</replaceable> ] [ MINVALUE <replaceable class="parameter">minvalue</replaceable> ] @@ -25,218 +25,207 @@ CREATE SEQUENCE <replaceable class="parameter">seqname</replaceable> [ START <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ CYCLE ] - </SYNOPSIS> + </synopsis> - <REFSECT2 ID="R2-SQL-CREATESEQUENCE-1"> - <REFSECT2INFO> - <DATE>1998-09-11</DATE> - </REFSECT2INFO> - <TITLE> + <refsect2 id="R2-SQL-CREATESEQUENCE-1"> + <refsect2info> + <date>1998-09-11</date> + </refsect2info> + <title> Inputs - </TITLE> - <PARA> - </PARA> - <VARIABLELIST> - <VARLISTENTRY> - <TERM> - <replaceable class="parameter">seqname</replaceable> - </TERM> - <LISTITEM> - <PARA> - The name of a sequence to be created. - </PARA> - </LISTITEM> - </VARLISTENTRY> - <VARLISTENTRY> - <TERM> - <replaceable class="parameter">increment</replaceable> - </TERM> - <LISTITEM> - <PARA> - The <option>INCREMENT <replaceable class="parameter">increment</replaceable></option> clause is optional. A positive value will make an - ascending sequence, a negative one a descending sequence. - The default value is one (1). - </PARA> - </LISTITEM> - </VARLISTENTRY> - <VARLISTENTRY> - <TERM> - <replaceable class="parameter">minvalue</replaceable> - </TERM> - <LISTITEM> - <PARA> - The optional clause <option>MINVALUE - <replaceable class="parameter">minvalue</replaceable></option> - determines the minimum value - a sequence can generate. The defaults are 1 and -2147483647 for - ascending and descending sequences, respectively. - </PARA> - </LISTITEM> - </VARLISTENTRY> - <VARLISTENTRY> - <TERM> - <replaceable class="parameter">maxvalue</replaceable> - </TERM> - <LISTITEM> - <PARA> - Use the optional clause <option>MAXVALUE - <replaceable class="parameter">maxvalue</replaceable></option> to - determine the maximum - value for the sequence. The defaults are 2147483647 and -1 for - ascending and descending sequences, respectively. - </PARA> - </LISTITEM> - </VARLISTENTRY> - <VARLISTENTRY> - <TERM> + </title> + <para> + + <variablelist> + <varlistentry> + <term><replaceable class="parameter">seqname</replaceable></term> + <listitem> + <para> + The name of a sequence to be created. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><replaceable class="parameter">increment</replaceable></term> + <listitem> + <para> + The + <option>INCREMENT <replaceable class="parameter">increment</replaceable></option> + clause is optional. A positive value will make an + ascending sequence, a negative one a descending sequence. + The default value is one (1). + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><replaceable class="parameter">minvalue</replaceable></term> + <listitem> + <para> + The optional clause <option>MINVALUE + <replaceable class="parameter">minvalue</replaceable></option> + determines the minimum value + a sequence can generate. The defaults are 1 and -2147483647 for + ascending and descending sequences, respectively. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><replaceable class="parameter">maxvalue</replaceable></term> + <listitem> + <para> + Use the optional clause <option>MAXVALUE + <replaceable class="parameter">maxvalue</replaceable></option> to + determine the maximum + value for the sequence. The defaults are 2147483647 and -1 for + ascending and descending sequences, respectively. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><replaceable class="parameter">start</replaceable></term> + <listitem> + <para> + The optional <option>START <replaceable class="parameter">start</replaceable> - </TERM> - <LISTITEM> - <PARA> - The optional <option>START - <replaceable class="parameter">start</replaceable> - clause</option> enables the sequence to begin anywhere. - The default starting value is - <replaceable class="parameter">minvalue</replaceable> - for ascending sequences and - <replaceable class="parameter">maxvalue</replaceable> - for descending ones. - </PARA> - </LISTITEM> - </VARLISTENTRY> - <VARLISTENTRY> - <TERM> - <replaceable class="parameter">cache</replaceable> - </TERM> - <LISTITEM> - <PARA> - The <option>CACHE <replaceable class="parameter">cache</replaceable></option> option - enables sequence numbers to be preallocated - and stored in memory for faster access. The minimum - value is 1 (only one value can be generated at a time, i.e. no cache) - and this is also the default. - </PARA> - </LISTITEM> - </VARLISTENTRY> - <VARLISTENTRY> - <TERM> - CYCLE - </TERM> - <LISTITEM> - <PARA> - The optional CYCLE keyword may be used to enable the sequence - to continue when the - <replaceable class="parameter">maxvalue</replaceable> or - <replaceable class="parameter">minvalue</replaceable> has been - reached by - an ascending or descending sequence respectively. If the limit is - reached, the next number generated will be whatever the - <replaceable class="parameter">minvalue</replaceable> or - <replaceable class="parameter">maxvalue</replaceable> is, - as appropriate. - </PARA> - </LISTITEM> - </VARLISTENTRY> - </variablelist> - </REFSECT2> - - <REFSECT2 ID="R2-SQL-CREATESEQUENCE-2"> - <REFSECT2INFO> - <DATE>1998-09-11</DATE> - </REFSECT2INFO> - <TITLE> + clause</option> enables the sequence to begin anywhere. + The default starting value is + <replaceable class="parameter">minvalue</replaceable> + for ascending sequences and + <replaceable class="parameter">maxvalue</replaceable> + for descending ones. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><replaceable class="parameter">cache</replaceable></term> + <listitem> + <para> + The <option>CACHE <replaceable class="parameter">cache</replaceable></option> option + enables sequence numbers to be preallocated + and stored in memory for faster access. The minimum + value is 1 (only one value can be generated at a time, i.e. no cache) + and this is also the default. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term>CYCLE</term> + <listitem> + <para> + The optional CYCLE keyword may be used to enable the sequence + to continue when the + <replaceable class="parameter">maxvalue</replaceable> or + <replaceable class="parameter">minvalue</replaceable> has been + reached by + an ascending or descending sequence respectively. If the limit is + reached, the next number generated will be whatever the + <replaceable class="parameter">minvalue</replaceable> or + <replaceable class="parameter">maxvalue</replaceable> is, + as appropriate. + </para> + </listitem> + </varlistentry> + </variablelist> + </para> + </refsect2> + + <refsect2 id="R2-SQL-CREATESEQUENCE-2"> + <refsect2info> + <date>1998-09-11</date> + </refsect2info> + <title> Outputs - </TITLE> - <PARA> + </title> + <para> - <VARIABLELIST> - <VARLISTENTRY> - <TERM> - <ReturnValue>CREATE</ReturnValue> - </TERM> - <LISTITEM> - <PARA> - Message returned if the command is successful. - </PARA> - </LISTITEM> - </VARLISTENTRY> - <VARLISTENTRY> - <TERM> -<ReturnValue>ERROR: amcreate: '<replaceable class="parameter">seqname</replaceable>' relation already exists</ReturnValue> - </TERM> - <LISTITEM> - <PARA> - If the sequence specified already exists. - </PARA> - </LISTITEM> - </VARLISTENTRY> - <VARLISTENTRY> - <TERM> -<ReturnValue>ERROR: DefineSequence: START value (<replaceable class="parameter">start</replaceable>) can't be > MAXVALUE (<replaceable class="parameter">maxvalue</replaceable>)</ReturnValue> - </TERM> - <LISTITEM> - <PARA> - If the specified starting value is out of range. - </PARA> - </LISTITEM> - </VARLISTENTRY> - <VARLISTENTRY> - <TERM> -<ReturnValue>ERROR: DefineSequence: START value (<replaceable class="parameter">start</replaceable>) can't be < MINVALUE (<replaceable class="parameter">minvalue</replaceable>)</ReturnValue> - </TERM> - <LISTITEM> - <PARA> - If the specified starting value is out of range. - </PARA> - </LISTITEM> - </VARLISTENTRY> - <VARLISTENTRY> - <TERM> -<ReturnValue>ERROR: DefineSequence: MINVALUE (<replaceable class="parameter">minvalue</replaceable>) can't be >= MAXVALUE (<replaceable class="parameter">maxvalue</replaceable>)</ReturnValue> - </TERM> - <LISTITEM> - <PARA> - If the minimum and maximum values are inconsistant. + <variablelist> + <varlistentry> + <term><computeroutput> +CREATE + </computeroutput></term> + <listitem> + <para> + Message returned if the command is successful. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><computeroutput> +ERROR: Relation '<replaceable class="parameter">seqname</replaceable>' already exists + </computeroutput></term> + <listitem> + <para> + If the sequence specified already exists. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><computeroutput> +ERROR: DefineSequence: MINVALUE (<replaceable class="parameter">start</replaceable>) can't be >= MAXVALUE (<replaceable class="parameter">max</replaceable>) + </computeroutput></term> + <listitem> + <para> + If the specified starting value is out of range. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><computeroutput> +ERROR: DefineSequence: START value (<replaceable class="parameter">start</replaceable>) can't be < MINVALUE (<replaceable class="parameter">min</replaceable>) + </computeroutput></term> + <listitem> + <para> + If the specified starting value is out of range. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><computeroutput> +ERROR: DefineSequence: MINVALUE (<replaceable class="parameter">min</replaceable>) can't be >= MAXVALUE (<replaceable class="parameter">max</replaceable>) + </computeroutput></term> + <listitem> + <para> + If the minimum and maximum values are inconsistant. </para> </listitem> </varlistentry> - </VARIABLELIST> + </variablelist> </para> - </REFSECT2> - </REFSYNOPSISDIV> - - <REFSECT1 ID="R1-SQL-CREATESEQUENCE-1"> - <REFSECT1INFO> - <DATE>1998-09-11</DATE> - </REFSECT1INFO> - <TITLE> + </refsect2> + </refsynopsisdiv> + + <refsect1 id="R1-SQL-CREATESEQUENCE-1"> + <refsect1info> + <date>1998-09-11</date> + </refsect1info> + <title> Description - </TITLE> - <PARA> - CREATE SEQUENCE will enter a new sequence number generator + </title> + <para> + <command>CREATE SEQUENCE</command> will enter a new sequence number generator into the current data base. This involves creating and initialising a new single-row table with the name <replaceable class="parameter">seqname</replaceable>. The generator will be "owned" by the user issuing the command. - </PARA> + </para> <para> After a sequence is created, you may use the function -<function>nextval(<replaceable class="parameter">seqname</replaceable>)</function> -to get a new number from the sequence. -The function -<function>currval('<replaceable class="parameter">seqname</replaceable>')</function> - may be used to determine the number returned by the last call to -<function>nextval(<replaceable class="parameter">seqname</replaceable>)</function> - for the specified sequence in the current session. -The function -<function>setval('<replaceable class="parameter">seqname</replaceable>', - <replaceable class="parameter">newvalue</replaceable>)</function> -may be used to set the current value of the specified sequence. -The next call to -<function>nextval(<replaceable class="parameter">seqname</replaceable>)</function> -will return the given value plus the sequence increment. + <function>nextval(<replaceable class="parameter">seqname</replaceable>)</function> + to get a new number from the sequence. + The function + <function>currval('<replaceable class="parameter">seqname</replaceable>')</function> + may be used to determine the number returned by the last call to + <function>nextval(<replaceable class="parameter">seqname</replaceable>)</function> + for the specified sequence in the current session. + The function + <function>setval('<replaceable class="parameter">seqname</replaceable>', + <replaceable class="parameter">newvalue</replaceable>)</function> + may be used to set the current value of the specified sequence. + The next call to + <function>nextval(<replaceable class="parameter">seqname</replaceable>)</function> + will return the given value plus the sequence increment. </para> - + <para> Use a query like <programlisting> @@ -256,7 +245,7 @@ SELECT last_value FROM sequence_name; calls to a generator. </para> -<caution> + <caution> <para> Unexpected results may be obtained if a cache setting greater than one is used for a sequence object that will be used concurrently by multiple @@ -279,35 +268,35 @@ SELECT last_value FROM sequence_name; whether or not it has yet been returned by nextval. </para> </caution> - - <REFSECT2 ID="R2-SQL-CREATESEQUENCE-3"> - <REFSECT2INFO> - <DATE>1998-09-11</DATE> - </REFSECT2INFO> - <TITLE> + + <refsect2 id="R2-SQL-CREATESEQUENCE-3"> + <refsect2info> + <date>1998-09-11</date> + </refsect2info> + <title> Notes - </TITLE> - <PARA> - Refer to the DROP SEQUENCE statement to remove a sequence. - </PARA> + </title> + <para> + Refer to the <command>DROP SEQUENCE</command> statement to remove a sequence. + </para> <para> Each backend uses its own cache to store allocated numbers. Numbers that are cached but not used in the current session will be lost, resulting in "holes" in the sequence. </para> - </REFSECT2> + </refsect2> </refsect1> - - <REFSECT1 ID="R1-SQL-CREATESEQUENCE-2"> - <TITLE> + + <refsect1 id="R1-SQL-CREATESEQUENCE-2"> + <title> Usage - </TITLE> - <PARA> + </title> + <para> Create an ascending sequence called <literal>serial</literal>, starting at 101: - </PARA> - <ProgramListing> + </para> + <programlisting> CREATE SEQUENCE serial START 101; - </ProgramListing> + </programlisting> <para> Select the next number from this sequence <programlisting> @@ -328,47 +317,45 @@ INSERT INTO distributors VALUES (NEXTVAL('serial'),'nothing'); <para> Set the sequence value after a COPY FROM: <programlisting> - CREATE FUNCTION distributors_id_max() RETURNS INT4 +CREATE FUNCTION distributors_id_max() RETURNS INT4 AS 'SELECT max(id) FROM distributors' LANGUAGE 'sql'; - BEGIN; +BEGIN; COPY distributors FROM 'input_file'; SELECT setval('serial', distributors_id_max()); - END; +END; </programlisting> </para> - - </REFSECT1> - - <REFSECT1 ID="R1-SQL-CREATESEQUENCE-3"> - <TITLE> + </refsect1> + + <refsect1 id="R1-SQL-CREATESEQUENCE-3"> + <title> Compatibility - </TITLE> - <PARA> + </title> + <para> <command>CREATE SEQUENCE</command> is a <productname>Postgres</productname> language extension. - </PARA> - - <REFSECT2 ID="R2-SQL-CREATESEQUENCE-4"> - <REFSECT2INFO> - <DATE>1998-09-11</DATE> - </REFSECT2INFO> - <TITLE> + </para> + + <refsect2 id="R2-SQL-CREATESEQUENCE-4"> + <refsect2info> + <date>1998-09-11</date> + </refsect2info> + <title> SQL92 - </TITLE> - <PARA> + </title> + <para> There is no <command>CREATE SEQUENCE</command> statement - in <acronym>SQL92</acronym>. - </PARA> + in <acronym>SQL92</acronym>. + </para> </refsect2> </refsect1> -</REFENTRY> - +</refentry> <!-- Keep this comment at the end of the file Local variables: mode: sgml -sgml-omittag:t +sgml-omittag:nil sgml-shorttag:t sgml-minimize-attributes:nil sgml-always-quote-attributes:t |