diff options
| -rw-r--r-- | doc/src/sgml/ref/create_table.sgml | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml index 771919f1646..511aacc73f3 100644 --- a/doc/src/sgml/ref/create_table.sgml +++ b/doc/src/sgml/ref/create_table.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/ref/create_table.sgml,v 1.80 2004/03/22 16:18:50 tgl Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/create_table.sgml,v 1.81 2004/05/19 23:10:43 momjian Exp $ PostgreSQL documentation --> @@ -383,10 +383,13 @@ and <replaceable class="PARAMETER">table_constraint</replaceable> is: <para> The <literal>CHECK</> clause specifies an expression producing a Boolean result which new or updated rows must satisfy for an - insert or update operation to succeed. A check constraint - specified as a column constraint should reference that column's - value only, while an expression appearing in a table constraint - may reference multiple columns. + insert or update operation to succeed. Expressions evaluating + to TRUE or UNKNOWN succeed. Should any row of an insert or + update operation produce a FALSE result an error exception is + raised and the insert or update does not alter the database. A + check constraint specified as a column constraint should + reference that column's value only, while an expression + appearing in a table constraint may reference multiple columns. </para> <para> |