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<chapter id="information-schema">

<title>The Information Schema</title>

<entry>

Update rule of the foreign key constraint:

<literal>CASCADE</literal>, <literal>SET NULL</literal>,

<literal>SET DEFAULT</literal>, <literal>RESTRICT</literal>,or

<literal>SET DEFAULT</literal>, <literal>RESTRICT</literal>,or

<literal>NO ACTION</literal>.

</entry>

</row>

<entry>

Delete rule of the foreign key constraint:

<literal>CASCADE</literal>, <literal>SET NULL</literal>,

<literal>SET DEFAULT</literal>, <literal>RESTRICT</literal>,or

<literal>SET DEFAULT</literal>, <literal>RESTRICT</literal>,or

<literal>NO ACTION</literal>.

</entry>

</row>

CREATEFUNCTION_pg_keyissubset(smallint[],smallint[]) RETURNSboolean

LANGUAGE sql

IMMUTABLE

RETURNSNULLONNULL INPUT

AS'select $1[1] is null or ($1[1] = any ($2) and coalesce(_pg_keyissubset($1[2:array_upper($1,1)], $2), true))';

CREATEFUNCTION_pg_keysequal(smallint[],smallint[]) RETURNSboolean

LANGUAGE sql

IMMUTABLE

RETURNSNULLONNULL INPUT

AS'select _pg_keyissubset($1, $2) and _pg_keyissubset($2, $1)';

SELECT CAST(current_database()AS sql_identifier)AS constraint_catalog,

CAST(ncon.nspnameAS sql_identifier)AS constraint_schema,

CAST(con.connameAS sql_identifier)AS constraint_name,

CAST(current_database()AS sql_identifier)AS unique_constraint_catalog,

CAST(

CASE WHENnpkc.nspname ISNULL THENNULL

ELSE current_database() END

AS sql_identifier)AS unique_constraint_catalog,

CAST(npkc.nspnameAS sql_identifier)AS unique_constraint_schema,

CAST(pkc.connameAS sql_identifier)AS unique_constraint_name,

WHEN'n' THEN'SET NULL'

WHEN'd' THEN'SET DEFAULT'

WHEN'r' THEN'RESTRICT'

WHEN'a' THEN'NOACTION' END

WHEN'a' THEN'NO ACTION' END

AS character_data)AS update_rule,

CAST(

CASEcon.confdeltype WHEN'c' THEN'CASCADE'

WHEN'n' THEN'SET NULL'

WHEN'd' THEN'SET DEFAULT'

WHEN'r' THEN'RESTRICT'

WHEN'a' THEN'NOACTION' END

WHEN'a' THEN'NO ACTION' END

AS character_data)AS delete_rule

FROM pg_namespace ncon,

pg_constraintcon,

pg_namespace npkc,

FROM(pg_namespace nconINNER JOIN pg_constraint conONncon.oid=con.connamespace

(pg_constraint pkcINNER JOINpg_namespace npkcONpkc.connamespace=npkc.oid)

WHEREncon.oid=con.connamespace

ANDcon.conrelid=c.oid

ANDcon.confkey=pkc.conkey

ANDpkc.connamespace=npkc.oid

ANDc.relowner=u.usesysid

ANDc.relkind='r'

WHEREc.relkind='r'

ANDcon.contype='f'

AND (pkc.contypeIN ('p','u')ORpkc.contype ISNULL)

ANDu.usename=current_user;

GRANTSELECTON referential_constraints TO PUBLIC;