diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/ref/create_type.sgml | 35 |
1 files changed, 22 insertions, 13 deletions
diff --git a/doc/src/sgml/ref/create_type.sgml b/doc/src/sgml/ref/create_type.sgml index 08f4c1464c7..038cf8c256f 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 1.70 2007/05/11 17:57:11 tgl Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/create_type.sgml,v 1.71 2007/05/12 00:54:59 tgl Exp $ PostgreSQL documentation --> @@ -530,18 +530,6 @@ CREATE TYPE <replaceable class="parameter">name</replaceable> <title>Notes</title> <para> - It is best to avoid using type names that begin with the underscore - character (<literal>_</literal>). <productname>PostgreSQL</productname> - forms the name of an array type by prepending one or more underscores - to the element type's name, and these names may collide with user-defined - type names that begin with underscore. While the system will modify - generated array type names to avoid collisions, this does not help if the - conflicting array type already exists when you try to create your type. - Also, various old client software may assume that names beginning with - underscores always represent arrays. - </para> - - <para> Because there are no restrictions on use of a data type once it's been created, creating a base type is tantamount to granting public execute permission on the functions mentioned in the type definition. (The creator @@ -553,6 +541,27 @@ CREATE TYPE <replaceable class="parameter">name</replaceable> </para> <para> + Before <productname>PostgreSQL</productname> version 8.3, the name of + a generated array type was always exactly the element type's name with one + underscore character (<literal>_</literal>) prepended. (Type names were + therefore restricted in length to one less character than other names.) + While this is still usually the case, the array type name may vary from + this in case of maximum-length names or collisions with user type names + that begin with underscore. Writing code that depends on this convention + is therefore deprecated. Instead, use + <structname>pg_type</>.<structfield>typarray</> to locate the array type + associated with a given type. + </para> + + <para> + It may be advisable to avoid using type and table names that begin with + underscore. While the server will change generated array type names to + avoid collisions with user-given names, there is still risk of confusion, + particularly with old client software that may assume that type names + beginning with underscores always represent arrays. + </para> + + <para> Before <productname>PostgreSQL</productname> version 8.2, the syntax <literal>CREATE TYPE <replaceable>name</></literal> did not exist. The way to create a new base type was to create its input function first. |