diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/bki.sgml | 52 |
1 files changed, 45 insertions, 7 deletions
diff --git a/doc/src/sgml/bki.sgml b/doc/src/sgml/bki.sgml index e3ba73a9a8d..0fb309a1bd9 100644 --- a/doc/src/sgml/bki.sgml +++ b/doc/src/sgml/bki.sgml @@ -217,12 +217,14 @@ <replaceable>value</replaceable> pairs. The allowed <replaceable>key</replaceable>s are the names of the catalog's columns, plus the metadata keys <literal>oid</literal>, - <literal>oid_symbol</literal>, and <literal>descr</literal>. + <literal>oid_symbol</literal>, + <literal>array_type_oid</literal>, and <literal>descr</literal>. (The use of <literal>oid</literal> and <literal>oid_symbol</literal> - is described in <xref linkend="system-catalog-oid-assignment"/> - below. <literal>descr</literal> supplies a description string for - the object, which will be inserted - into <structname>pg_description</structname> + is described in <xref linkend="system-catalog-oid-assignment"/> below, + while <literal>array_type_oid</literal> is described in + <xref linkend="system-catalog-auto-array-types"/>. + <literal>descr</literal> supplies a description string for the object, + which will be inserted into <structname>pg_description</structname> or <structname>pg_shdescription</structname> as appropriate.) While the metadata keys are optional, the catalog's defined columns must all be provided, except when the catalog's <literal>.h</literal> @@ -282,8 +284,9 @@ <para> Within each pair of curly braces, the metadata fields <literal>oid</literal>, <literal>oid_symbol</literal>, - and <literal>descr</literal> (if present) come first, in that - order, then the catalog's own fields appear in their defined order. + <literal>array_type_oid</literal>, and <literal>descr</literal> + (if present) come first, in that order, then the catalog's own + fields appear in their defined order. </para> </listitem> @@ -498,6 +501,41 @@ </para> </sect2> + <sect2 id="system-catalog-auto-array-types"> + <title>Automatic Creation of Array Types</title> + + <para> + Most scalar data types should have a corresponding array type (that is, + a standard varlena array type whose element type is the scalar type, and + which is referenced by the <structfield>typarray</structfield> field of + the scalar type's <structname>pg_type</structname> + entry). <filename>genbki.pl</filename> is able to generate + the <structname>pg_type</structname> entry for the array type + automatically in most cases. + </para> + + <para> + To use this facility, just write an <literal>array_type_oid + => <replaceable>nnnn</replaceable></literal> metadata field in the + scalar type's <structname>pg_type</structname> entry, specifying the OID + to use for the array type. You may then omit + the <structfield>typarray</structfield> field, since it will be filled + automatically with that OID. + </para> + + <para> + The generated array type's name is the scalar type's name with an + underscore prepended. The array entry's other fields are filled from + <literal>BKI_ARRAY_DEFAULT(<replaceable>value</replaceable>)</literal> + annotations in <filename>pg_type.h</filename>, or if there isn't one, + copied from the scalar type. (There's also a special case + for <structfield>typalign</structfield>.) Then + the <structfield>typelem</structfield> + and <structfield>typarray</structfield> fields of the two entries are + set to cross-reference each other. + </para> + </sect2> + <sect2 id="system-catalog-recipes"> <title>Recipes for Editing Data Files</title> |