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Commit 6787c6c9 authored by Bruce Momjian's avatar Bruce Momjian
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Updates create_function.sgml with fixes for new foreign keys

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doc/TODO
View file @ 6787c6c9
TODO list for PostgreSQL
========================
Last updated: Thu Mar 23 01:35:33 EST 2000
Last updated: Fri Apr 14 16:07:41 EDT 2000
Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
......@@ -309,6 +309,7 @@ SOURCE CODE
* Remove SET KSQO option if OR processing is improved(Tom)
* -Pre-generate lex and yacc output so not required for install(Peter E)
* Use macros to define NT open() file parameters, remove NT-specific defines
* Change CURRENT to OLD internally for rules
---------------------------------------------------------------------------
......
doc/src/sgml/ref/create_table.sgml
View file @ 6787c6c9
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_table.sgml,v 1.22 2000/04/13 07:19:27 momjian Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_table.sgml,v 1.23 2000/04/14 21:44:21 momjian Exp $
Postgres documentation
-->
......@@ -97,15 +97,16 @@ CREATE [ TEMPORARY | TEMP ] TABLE <replaceable class="PARAMETER">table</replacea
<term><replaceable>column_constraint_clause</replaceable></term>
<listitem>
<para>
The optional column constraint clauses specify a list of integrity
constraints or tests which new or updated entries must satisfy for
an insert or update operation to succeed. Each constraint
must evaluate to a boolean expression. Although <acronym>SQL92</acronym>
requires the <replaceable class="PARAMETER">column_constraint_clause</replaceable>
to refer to that column only, <productname>Postgres</productname>
allows multiple columns
to be referenced within a single column constraint.
See the column constraint clause for more information.
The optional column constraint clauses specify a list of
integrity constraints or tests which new or updated entries must
satisfy for an insert or update operation to succeed. Each
constraint must evaluate to a boolean expression. Although
<acronym>SQL92</acronym> requires the <replaceable
class="PARAMETER">column_constraint_clause</replaceable> to
refer to that column only, <productname>Postgres</productname>
allows multiple columns to be referenced within a single column
constraint. See the column constraint clause for more
information.
</para>
</listitem>
</varlistentry>
......@@ -114,16 +115,16 @@ CREATE [ TEMPORARY | TEMP ] TABLE <replaceable class="PARAMETER">table</replacea
<term><replaceable>table_constraint_clause</replaceable></term>
<listitem>
<para>
The optional table CONSTRAINT clause specifies a list of integrity
constraints which new or updated entries must satisfy for
an insert or update operation to succeed. Each constraint
must evaluate to a boolean expression. Multiple columns
may be referenced within a single constraint.
Only one PRIMARY KEY clause may be specified for a table;
PRIMARY KEY <replaceable>column</replaceable>
(a table constraint) and PRIMARY KEY (a column constraint) are
mutually exclusive..
See the table constraint clause for more information.
The optional table CONSTRAINT clause specifies a
list of integrity constraints which new or updated entries must
satisfy for an insert or update operation to succeed. Each
constraint must evaluate to a boolean expression. Multiple
columns may be referenced within a single constraint. Only one
PRIMARY KEY clause may be specified for a table;
PRIMARY KEY <replaceable>column</replaceable> (a table
constraint) and PRIMARY KEY (a column constraint)
are mutually exclusive.. See the table constraint clause for
more information.
</para>
</listitem>
</varlistentry>
......@@ -140,13 +141,6 @@ CREATE [ TEMPORARY | TEMP ] TABLE <replaceable class="PARAMETER">table</replacea
<productname>Postgres</productname> automatically allows the created
table to inherit functions on tables above it in the inheritance
hierarchy.
<note>
<title>Aside</title>
<para>
Inheritance of functions is done according
to the conventions of the Common Lisp Object System (CLOS).
</para>
</note>
</para>
</listitem>
</varlistentry>
......@@ -227,7 +221,7 @@ ERROR: DEFAULT: type mismatched
<para>
<note>
<para>
As of Postgres version 6.0, consistant array dimensions within an
As of Postgres version 6.0, consistent array dimensions within an
attribute are not enforced. This will likely change in a future
release.
</para>
......@@ -353,13 +347,13 @@ DEFAULT <replaceable class="PARAMETER">value</replaceable>
<varlistentry>
<term>SESSION_USER</term>
<listitem>
<simpara>not yet supported</simpara>
<simpara>See CURRENT_USER function</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term>SYSTEM_USER</term>
<listitem>
<simpara>not yet supported</simpara>
<simpara>See CURRENT_USER function</simpara>
</listitem>
</varlistentry>
</variablelist>
......@@ -502,9 +496,9 @@ CREATE TABLE distributors (
<listitem>
<para>
This column is a primary key, which implies that uniqueness is
enforced by the system and that other tables may rely on this column
as a unique identifier for rows.
See PRIMARY KEY for more information.
enforced by the system and that other tables may rely on this
column as a unique identifier for rows. See PRIMARY KEY for more
information.
</para>
</listitem>
</varlistentry>
......@@ -529,13 +523,12 @@ CREATE TABLE distributors (
</title>
<para>
The optional constraint
clauses specify constraints or tests which new or updated entries
must satisfy for an insert or update operation to succeed. Each constraint
must evaluate to a boolean expression. Multiple attributes may be referenced within
a single constraint. The use of PRIMARY KEY
as a table constraint
is mutually incompatible with PRIMARY KEY as a column constraint.
The optional constraint clauses specify constraints or tests which
new or updated entries must satisfy for an insert or update
operation to succeed. Each constraint must evaluate to a boolean
expression. Multiple attributes may be referenced within a single
constraint. The use of PRIMARY KEY as a table constraint is mutually
incompatible with PRIMARY KEY as a column constraint.
</para>
<para>
......@@ -550,10 +543,9 @@ CREATE TABLE distributors (
</para>
<para>
A column constraint is an integrity constraint defined as part
of a column definition, and logically becomes a table
constraint as soon as it is created. The column
constraints available are:
A column constraint is an integrity constraint defined as part of a
column definition, and logically becomes a table constraint as soon
as it is created. The column constraints available are:
<simplelist columns="1">
<member>PRIMARY KEY</member>
......@@ -563,14 +555,6 @@ CREATE TABLE distributors (
<member>NOT NULL</member>
</simplelist>
</para>
<note>
<para>
<productname>Postgres</productname> now
(new for v7.0) supports
REFERENCES integrity constraints.
</para>
</note>
</refsect2>
<refsect2 id="R2-SQL-NOTNULL-1">
......@@ -711,10 +695,10 @@ ERROR: Cannot insert a duplicate key into a unique index.
The column definitions of the specified columns do not have to
include a NOT NULL constraint to be included in a UNIQUE
constraint. Having more than one null value in a column without a
NOT NULL constraint, does not violate a UNIQUE constraint.
(This deviates from the <acronym>SQL92</acronym> definition, but
is a more sensible convention. See the section on compatibility
for more details.).
NOT NULL constraint, does not violate a UNIQUE constraint. (This
deviates from the <acronym>SQL92</acronym> definition, but is a
more sensible convention. See the section on compatibility for more
details.).
</para>
<para>
Each UNIQUE column constraint must name a column that is
......@@ -827,14 +811,13 @@ ERROR: ExecAppend: rejected due to CHECK constraint "<replaceable class="parame
<title>Description</title>
<para>
The CHECK constraint specifies a restriction on allowed values
within a column.
The CHECK constraint is also allowed as a table constraint.
within a column. The CHECK constraint is also allowed as a table
constraint.
</para>
<para>
The SQL92 CHECK column constraints can only be defined on, and
refer to, one column of the table. <productname>Postgres</productname>
does not have
this restriction.
refer to, one column of the table.
<productname>Postgres</productname> does not have this restriction.
</para>
</refsect3>
</refsect2>
......@@ -883,11 +866,11 @@ ERROR: Cannot insert a duplicate key into a unique index.
<refsect3>
<title>Description</title>
<para>
The PRIMARY KEY column constraint specifies that a column of a table
may contain only unique
(non-duplicate), non-NULL values. The definition of
the specified column does not have to include an explicit NOT NULL
constraint to be included in a PRIMARY KEY constraint.
The PRIMARY KEY column constraint specifies that a column of a
table may contain only unique (non-duplicate), non-NULL values. The
definition of the specified column does not have to include an
explicit NOT NULL constraint to be included in a PRIMARY KEY
constraint.
</para>
<para>
Only one PRIMARY KEY can be specified for a table.
......@@ -974,9 +957,11 @@ ERROR: Cannot insert a duplicate key into a unique index.
<term>MATCH <replaceable class="parameter">matchtype</replaceable></term>
<listitem>
<para>
The type of comparison to do between the table data. There are three
types of matching, MATCH FULL, MATCH PARTIAL, and the unspecified match type
used if no match type is specified.
The type of comparison to do between the table data. There are
three types of matching, MATCH FULL, MATCH PARTIAL, and the
unspecified match type used if no match type is specified.
MATCH PARTIAL is not
currently supported.
</para>
</listitem>
</varlistentry>
......@@ -988,10 +973,10 @@ ERROR: Cannot insert a duplicate key into a unique index.
deleted. There are the following actions.
<variablelist>
<varlistentry>
<term>CASCADE</term>
<term>NO ACTION</term>
<listitem>
<para>
Delete any rows referencing the deleted row.
Produce error if foreign key violated. This is the default.
</para>
</listitem>
</varlistentry>
......@@ -999,31 +984,31 @@ ERROR: Cannot insert a duplicate key into a unique index.
<term>RESTRICT</term>
<listitem>
<para>
Disallow deletion of rows being referenced.
Same as NO ACTION.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>SET NULL</term>
<term>CASCADE</term>
<listitem>
<para>
Set the referencing column values to NULL.
Delete any rows referencing the deleted row.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>SET DEFAULT</term>
<term>SET NULL</term>
<listitem>
<para>
Set the referencing column values to their default value.
Set the referencing column values to NULL.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>NO ACTION</term>
<term>SET DEFAULT</term>
<listitem>
<para>
Do nothing.
Set the referencing column values to their default value.
</para>
</listitem>
</varlistentry>
......@@ -1035,16 +1020,16 @@ ERROR: Cannot insert a duplicate key into a unique index.
<term>ON UPDATE <replaceable class="parameter">action</replaceable></term>
<listitem>
<para>
The action to do when a referenced column in the referenced table is being
updated to a new value. If the row is updated, but the referenced column
is not changed, no action is done. There are the following actions.
The action to do when a referenced column in the referenced
table is being updated to a new value. If the row is updated,
but the referenced column is not changed, no action is done.
There are the following actions.
<variablelist>
<varlistentry>
<term>CASCADE</term>
<term>NO ACTION</term>
<listitem>
<para>
Update the value of the referencing column to the new value of the
referenced column.
Produce error if foreign key violated. This is the default.
</para>
</listitem>
</varlistentry>
......@@ -1052,31 +1037,32 @@ ERROR: Cannot insert a duplicate key into a unique index.
<term>RESTRICT</term>
<listitem>
<para>
Disallow update of row being referenced.
Same as NO ACTION.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>SET NULL</term>
<term>CASCADE</term>
<listitem>
<para>
Set the referencing column values to NULL.
Update the value of the referencing column to the new value of the
referenced column.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>SET DEFAULT</term>
<term>SET NULL</term>
<listitem>
<para>
Set the referencing column values to their default value.
Set the referencing column values to NULL.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>NO ACTION</term>
<term>SET DEFAULT</term>
<listitem>
<para>
Do nothing.
Set the referencing column values to their default value.
</para>
</listitem>
</varlistentry>
......@@ -1089,8 +1075,10 @@ ERROR: Cannot insert a duplicate key into a unique index.
<term> [ NOT ] DEFERRABLE </term>
<listitem>
<para>
Tells the trigger manager whether this constraint may be
deferred to the end of transaction.
This controls whether the constraint can be deferred to the end
of the transaction. If DEFERRABLE, SET CONSTRAINTS ALL DEFERRED
will cause the foreign key to be checked only at the end of the
transaction. NOT DEFERRABLE is the default.
</para>
</listitem>
</varlistentry>
......@@ -1101,22 +1089,20 @@ ERROR: Cannot insert a duplicate key into a unique index.
<para>
<replaceable class="parameter">checktime</replaceable> has two possible values
which specify the default time to check the constraint.
<variablelist>
<varlistentry>
<term>DEFERRED</term>
<listitem>
<para>
Check this constraint at the end of the transaction.
Check constraint only at the end of the transaction.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>IMMEDIATE</term>
<listitem>
<para>
Check this constraint after each statement.
Check constraint after each statement. This is the default.
</para>
</listitem>
</varlistentry>
......@@ -1167,16 +1153,15 @@ ERROR: <replaceable class="parameter">name</replaceable> referential integrity
<refsect3 id="R3-SQL-REFERENCES-3">
<title>Description</title>
<para>
The REFERENCES column constraint specifies that a column of a
table must only contain values which match against values
in a referenced column of a referenced table.
The REFERENCES column constraint specifies that a
column of a table must only contain values which match against
values in a referenced column of a referenced table.
</para>
<para>
A value added to this column are matched against the
values of the referenced table and referenced column using
the given match type.
In addition, when the referenced column data is changed,
actions are run upon this column's matching data.
A value added to this column are matched against the values of the
referenced table and referenced column using the given match type.
In addition, when the referenced column data is changed, actions
are run upon this column's matching data.
</para>
</refsect3>
......@@ -1188,12 +1173,11 @@ ERROR: <replaceable class="parameter">name</replaceable> referential integrity
Notes
</title>
<para>
Currently <productname>Postgres</productname> only supports
MATCH FULL and an unspecified match type.
In addition, the referenced columns are supposed to be
the columns of a UNIQUE constraint in the referenced table,
however <productname>Postgres</productname> does not
enforce this.
Currently <productname>Postgres</productname> only supports MATCH
FULL and an unspecified match type. In addition, the referenced
columns are supposed to be the columns of a UNIQUE constraint in
the referenced table, however <productname>Postgres</productname>
does not enforce this.
</para>
</refsect3>
</refsect2>
......@@ -1281,14 +1265,6 @@ ERROR: <replaceable class="parameter">name</replaceable> referential integrity
<member>FOREIGN KEY</member>
</simplelist>
</para>
<note>
<para>
<productname>Postgres</productname> now
supports FOREIGN KEY
integrity constraints
</para>
</note>
</refsect2>
<refsect2 id="R2-SQL-UNIQUECLAUSE-4">
......@@ -1354,10 +1330,11 @@ ERROR: <replaceable class="parameter">name</replaceable> referential integrity
</title>
<para>
The UNIQUE constraint specifies a rule that a group of one or
more distinct columns of a table may contain only unique values.
The behavior of the UNIQUE table constraint is the same as that for column
constraints, with the additional capability to span multiple columns.
The UNIQUE constraint specifies a rule that a group of one or more
distinct columns of a table may contain only unique values. The
behavior of the UNIQUE table constraint is the same as that for
column constraints, with the additional capability to span multiple
columns.
</para>
<para>
See the section on the UNIQUE column constraint for more details.
......@@ -1428,8 +1405,8 @@ CREATE TABLE distributors (
<term>ERROR: Cannot insert a duplicate key into a unique index.</term>
<listitem>
<para>
This occurs at run-time if one tries to insert a duplicate value into
a column subject to a PRIMARY KEY constraint.
This occurs at run-time if one tries to insert a duplicate
value into a column subject to a PRIMARY KEY constraint.
</para>
</listitem>
</varlistentry>
......@@ -1479,10 +1456,9 @@ FOREIGN KEY ( <replaceable class="parameter">column</replaceable> [, ...] ) REFE
[ INITIALLY <replaceable class="parameter">checktime</replaceable> ]
</synopsis>
<para>
The REFERENCES constraint specifies a rule that a column
value is checked against the values of another column.
REFERENCES can also be specified as part of
a FOREIGN KEY table constraint.
The REFERENCES constraint specifies a rule that a column value is
checked against the values of another column. REFERENCES can also be
specified as part of a FOREIGN KEY table constraint.
</para>
<refsect3 id="R3-SQL-REFERENCES-5">
......@@ -1527,9 +1503,10 @@ FOREIGN KEY ( <replaceable class="parameter">column</replaceable> [, ...] ) REFE
<term>MATCH <replaceable class="parameter">matchtype</replaceable></term>
<listitem>
<para>
The type of comparison to do between the table data. There are three
types of matching, MATCH FULL, MATCH PARTIAL, and the unspecified match type
used if no match type is specified.
The type of comparison to do between the table data. There are
three types of matching, MATCH FULL, MATCH PARTIAL, and the
unspecified match type used if no match type is specified.
MATCH PARTIAL is not currently supported.
</para>
</listitem>
</varlistentry>
......@@ -1541,10 +1518,10 @@ FOREIGN KEY ( <replaceable class="parameter">column</replaceable> [, ...] ) REFE
deleted. There are the following actions.
<variablelist>
<varlistentry>
<term>CASCADE</term>
<term>NO ACTION</term>
<listitem>
<para>
Delete any rows referencing the deleted row.
Produce error if foreign key violated. This is the default.
</para>
</listitem>
</varlistentry>
......@@ -1552,31 +1529,31 @@ FOREIGN KEY ( <replaceable class="parameter">column</replaceable> [, ...] ) REFE
<term>RESTRICT</term>
<listitem>
<para>
Disallow deletion of rows being referenced.
Same as NO ACTION.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>SET NULL</term>
<term>CASCADE</term>
<listitem>
<para>
Set the referencing column values to NULL.
Delete any rows referencing the deleted row.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>SET DEFAULT</term>
<term>SET NULL</term>
<listitem>
<para>
Set the referencing column values to their default value.
Set the referencing column values to NULL.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>NO ACTION</term>
<term>SET DEFAULT</term>
<listitem>
<para>
Do nothing.
Set the referencing column values to their default value.
</para>
</listitem>
</varlistentry>
......@@ -1588,16 +1565,16 @@ FOREIGN KEY ( <replaceable class="parameter">column</replaceable> [, ...] ) REFE
<term>ON UPDATE <replaceable class="parameter">action</replaceable></term>
<listitem>
<para>
The action to do when a referenced column in the referenced table is being
updated to a new value. If the row is updated, but the referenced column
is not changed, no action is done. There are the following actions.
The action to do when a referenced column in the referenced
table is being updated to a new value. If the row is updated,
but the referenced column is not changed, no action is done.
There are the following actions.
<variablelist>
<varlistentry>
<term>CASCADE</term>
<term>NO ACTION</term>
<listitem>
<para>
Update the value of the referencing column to the new value of the
referenced column.
Produce error if foreign key violated. This is the default.
</para>
</listitem>
</varlistentry>
......@@ -1610,26 +1587,27 @@ FOREIGN KEY ( <replaceable class="parameter">column</replaceable> [, ...] ) REFE
</listitem>
</varlistentry>
<varlistentry>
<term>SET NULL</term>
<term>CASCADE</term>
<listitem>
<para>
Set the referencing column values to NULL.
Update the value of the referencing column to the new value
of the referenced column.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>SET DEFAULT</term>
<term>SET NULL</term>
<listitem>
<para>
Set the referencing column values to their default value.
Set the referencing column values to NULL.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>NO ACTION</term>
<term>SET DEFAULT</term>
<listitem>
<para>
Do nothing.
Set the referencing column values to their default value.
</para>
</listitem>
</varlistentry>
......@@ -1641,8 +1619,10 @@ FOREIGN KEY ( <replaceable class="parameter">column</replaceable> [, ...] ) REFE
<term> [ NOT ] DEFERRABLE </term>
<listitem>
<para>
Tells the trigger manager whether this constraint may be
deferred to the end of transaction.
This controls whether the constraint can be deferred to the end
of the transaction. If DEFERRABLE, SET CONSTRAINTS ALL DEFERRED
will cause the foreign key to be checked only at the end of the
transaction. NOT DEFERRABLE is the default.
</para>
</listitem>
</varlistentry>
......@@ -1650,22 +1630,23 @@ FOREIGN KEY ( <replaceable class="parameter">column</replaceable> [, ...] ) REFE
<term>INITIALLY <replaceable class="parameter">checktime</replaceable></term>
<listitem>
<para>
<replaceable class="parameter">checktime</replaceable> has two possible values
which specify the default time to check the constraint.
<replaceable class="parameter">checktime</replaceable> has two
possible values which specify the default time to check the
constraint.
<variablelist>
<varlistentry>
<term>DEFERRED</term>
<term>IMMEDIATE</term>
<listitem>
<para>
Check this constraint at the end of the transaction.
Check constraint after each statement. This is the default.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>IMMEDIATE</term>
<term>DEFERRED</term>
<listitem>
<para>
Check this constraint after each statement.
Check constraint only at the end of the transaction.
</para>
</listitem>
</varlistentry>
......@@ -1719,8 +1700,9 @@ ERROR: <replaceable class="parameter">name</replaceable> referential integrity
</para>
<para>
The FOREIGN KEY table constraint is similar to that for column constraints,
with the additional capability of encompassing multiple columns.
The FOREIGN KEY table constraint is similar to that for column
constraints, with the additional capability of encompassing
multiple columns.
</para>
<para>
Refer to the section on the FOREIGN KEY column constraint for more
......@@ -1886,10 +1868,10 @@ CREATE GLOBAL TEMPORARY TABLE <replaceable class="parameter">table</replaceable>
constraints.
</para>
<para>
The optional ON COMMIT clause of CREATE TEMPORARY TABLE
specifies whether or not the temporary table should be emptied of
rows whenever COMMIT is executed. If the ON COMMIT clause is
omitted, the default option, ON COMMIT DELETE ROWS, is assumed.
The optional ON COMMIT clause of CREATE TEMPORARY TABLE specifies
whether or not the temporary table should be emptied of rows
whenever COMMIT is executed. If the ON COMMIT clause is omitted, the
default option, ON COMMIT DELETE ROWS, is assumed.
</para>
<para>
To create a temporary table:
......@@ -1936,10 +1918,10 @@ CREATE TEMPORARY TABLE actors (
NULL clause
</title>
<para>
The NULL "constraint" (actually a non-constraint)
is a <productname>Postgres</productname> extension to SQL92
is included for symmetry with the NOT NULL clause. Since it is the default
for any column, its presence is simply noise.
The NULL "constraint" (actually a non-constraint) is a
<productname>Postgres</productname> extension to SQL92 is
included for symmetry with the NOT NULL clause. Since it is the
default for any column, its presence is simply noise.
<synopsis>
[ CONSTRAINT name ] NULL
</synopsis>
......@@ -2001,11 +1983,10 @@ the column. Not our problem...
</para>
<para>
An assertion is a special type of integrity constraint and share
the same namespace as other constraints.
However, an assertion is not necessarily dependent on one
particular base table as constraints are, so SQL-92 provides the
CREATE ASSERTION statement as an alternate method for defining a
constraint:
the same namespace as other constraints. However, an assertion is
not necessarily dependent on one particular base table as
constraints are, so SQL-92 provides the CREATE ASSERTION statement
as an alternate method for defining a constraint:
</para>
<synopsis>
CREATE ASSERTION name CHECK ( condition )
......@@ -2053,8 +2034,9 @@ CREATE ASSERTION name CHECK ( condition )
<term>NOT DEFERRABLE</term>
<listitem>
<para>
means that the Constraint must be checked for
violation of its rule after the execution of every SQL statement.
The constraint must be checked at the end of each statement.
SET CONSTRAINTS ALL DEFERRED will have no effect on this type
of constraint.
</para>
</listitem>
</varlistentry>
......@@ -2062,8 +2044,10 @@ CREATE ASSERTION name CHECK ( condition )
<term>DEFERRABLE</term>
<listitem>
<para>
means that checking of the Constraint may be deferred
until some later time, but no later than the end of the current
This controls whether the constraint can be deferred to the end
of the transaction. If SET CONSTRAINTS ALL DEFERRED is used or
the constraint is set to INITIALLY DEFERRED, this will cause
the foreign key to be checked only at the end of the
transaction.
</para>
</listitem>
......@@ -2079,9 +2063,8 @@ CREATE ASSERTION name CHECK ( condition )
<term>INITIALLY IMMEDIATE</term>
<listitem>
<para>
means that, as of the start of the transaction,
the Constraint must be checked for violation of its rule after the
execution of every SQL statement.
Check constraint only at the end of the transaction. This
is the default
</para>
</listitem>
</varlistentry>
......@@ -2089,9 +2072,8 @@ CREATE ASSERTION name CHECK ( condition )
<term>INITIALLY DEFERRED</term>
<listitem>
<para>
means that, as of the start of the transaction,
checking of the Constraint may be deferred until some later time,
but no later than the end of the current transaction.</para>
Check constraint after each statement.
</para>
</listitem>
</varlistentry>
</variablelist>
......
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