diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/ref/create_domain.sgml | 45 | ||||
| -rw-r--r-- | doc/src/sgml/ref/create_type.sgml | 3 |
2 files changed, 20 insertions, 28 deletions
diff --git a/doc/src/sgml/ref/create_domain.sgml b/doc/src/sgml/ref/create_domain.sgml index 4beb0ae53b8..bfed9027399 100644 --- a/doc/src/sgml/ref/create_domain.sgml +++ b/doc/src/sgml/ref/create_domain.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/ref/create_domain.sgml,v 1.27 2005/12/25 01:41:15 neilc Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/create_domain.sgml,v 1.28 2006/04/05 22:11:54 tgl Exp $ PostgreSQL documentation --> @@ -35,8 +35,10 @@ where <replaceable class="PARAMETER">constraint</replaceable> is: <title>Description</title> <para> - <command>CREATE DOMAIN</command> creates a new data domain. The - user who defines a domain becomes its owner. + <command>CREATE DOMAIN</command> creates a new domain. A domain is + essentially a data type with optional constraints (restrictions on + the allowed set of values). + The user who defines a domain becomes its owner. </para> <para> @@ -48,24 +50,13 @@ where <replaceable class="PARAMETER">constraint</replaceable> is: </para> <para> - Domains are useful for abstracting common fields between tables - into a single location for maintenance. For example, an email address - column may be used in several tables, all with the same properties. - Define a domain and use that rather than setting up each table's - constraints individually. + Domains are useful for abstracting common constraints on fields into + a single location for maintenance. For example, several tables might + contain email address columns, all requiring the same CHECK constraint + to verify the address syntax. + Define a domain rather than setting up each table's constraint + individually. </para> - - <caution> - <para> - At present, declaring a function result value as a domain - is pretty dangerous, because none of the procedural languages enforce domain constraints - on their results. You'll need to make sure that the function code itself - respects the constraints. In <application>PL/pgSQL</>, one possible - workaround is to explicitly cast the result value to the domain type - when you return it. <application>PL/pgSQL</> does not enforce domain - constraints for local variables within functions, either. - </para> - </caution> </refsect1> <refsect1> @@ -156,7 +147,7 @@ where <replaceable class="PARAMETER">constraint</replaceable> is: <literal>CHECK</> clauses specify integrity constraints or tests which values of the domain must satisfy. Each constraint must be an expression - producing a Boolean result. It should use the name <literal>VALUE</> + producing a Boolean result. It should use the key word <literal>VALUE</> to refer to the value being tested. </para> @@ -185,12 +176,12 @@ OR VALUE ~ '^\\d{5}-\\d{4}$' ); CREATE TABLE us_snail_addy ( - address_id SERIAL PRIMARY KEY -, street1 TEXT NOT NULL -, street2 TEXT -, street3 TEXT -, city TEXT NOT NULL -, postal us_postal_code NOT NULL + address_id SERIAL PRIMARY KEY, + street1 TEXT NOT NULL, + street2 TEXT, + street3 TEXT, + city TEXT NOT NULL, + postal us_postal_code NOT NULL ); </programlisting> </para> diff --git a/doc/src/sgml/ref/create_type.sgml b/doc/src/sgml/ref/create_type.sgml index e3b8b44d8f9..68ec242ae5a 100644 --- a/doc/src/sgml/ref/create_type.sgml +++ b/doc/src/sgml/ref/create_type.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/ref/create_type.sgml,v 1.62 2006/04/04 19:35:32 tgl Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/create_type.sgml,v 1.63 2006/04/05 22:11:54 tgl Exp $ PostgreSQL documentation --> @@ -591,6 +591,7 @@ CREATE TABLE big_objs ( <member><xref linkend="sql-createfunction" endterm="sql-createfunction-title"></member> <member><xref linkend="sql-droptype" endterm="sql-droptype-title"></member> <member><xref linkend="sql-altertype" endterm="sql-altertype-title"></member> + <member><xref linkend="sql-createdomain" endterm="sql-createdomain-title"></member> </simplelist> </refsect1> |