diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/contrib-spi.sgml | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/doc/src/sgml/contrib-spi.sgml b/doc/src/sgml/contrib-spi.sgml index 55d3fac7a69..6fa9479d1b9 100644 --- a/doc/src/sgml/contrib-spi.sgml +++ b/doc/src/sgml/contrib-spi.sgml @@ -81,10 +81,12 @@ <para> <function>autoinc()</function> is a trigger that stores the next value of a sequence into an integer field. This has some overlap with the - built-in <quote>serial column</quote> feature, but it is not the same: - <function>autoinc()</function> will override attempts to substitute a - different field value during inserts, and optionally it can be - used to increment the field during updates, too. + built-in <quote>serial column</quote> feature, but it is not the same. + The trigger will replace the field's value only if that value is + initially zero or null (after the action of the SQL statement that + inserted or updated the row). Also, if the sequence's next value is + zero, <function>nextval()</function> will be called a second time in + order to obtain a non-zero value. </para> <para> |