"Not Enforced" Table Constraints

A constraint that is not enforced is not really a constraint within the meaning of the act, but SQL does have such a concept and it needs to be mentioned here. With the exception of UNIQUE and PRIMARY KEY specifications, a table constraint can be declared as either ENFORCED (the default option) or NOT ENFORCED. The "enforcement characteristic" of such a constraint can be changed by means of an ALTER TABLE statement. For example, the table constraint MAX_ENROLMENTS becomes not enforced by execution of the statement ALTER TABLE ALTER CONSTRAINT MAX_ENROLMENTS NOT ENFORCED. The immediate effect is the same (ignoring effects on the catalog) as if ALTER TABLE DROP CONSTRAINT MAX_ENROLMENTS had been given. However, it's easier to reinstate the constraint using ALTER TABLE ALTER CONSTRAINT MAX_ENROLMENTS ENFORCED. NOT ENFORCED cannot be specified for domain constraints or assertions, so use of CREATE ASSERTION should really be the preferred method of declaring a constraint, but unfortunately that option is not widely available.

Posted Date: 1/18/2013 7:18:19 AM | Location : United States

Ask an Expert

Related Discussions:- "not enforced" table constraints - sql, Assignment Help, Ask Question on "not enforced" table constraints - sql, Get Answer, Expert's Help, "not enforced" table constraints - sql Discussions

Write discussion on "not enforced" table constraints - sql
Your posts are moderated

Write your message here..

Related Questions

Updating by insertion, Updating by insertion Syntax : INSERT IN... Updating by insertion Syntax : INSERT INTO ENROLMENT VALUES (SID ('S4'), 'Devinder', CID ('C1'));

When or then key constraints, WHEN or THEN Key Constraints Suppose a t... WHEN or THEN Key Constraints Suppose a table has two columns representing a period of time throughout which the information conveyed by the other columns is recorded as having

Table literals - sql, Table Literals - SQL One might expect SQL to sup... Table Literals - SQL One might expect SQL to support table literals in the manner illustrated in Example 2.2, but in fact that is not a legal SQL expression. Example: Not a

Join and and in sql, JOIN and AND in SQL In this Section is all about ... JOIN and AND in SQL In this Section is all about one operator, JOIN. SQL's closest counterpart, NATURAL JOIN, has already been covered. Here we look at several other "join" op

Advantages of packages, Advantages of Packages The benefits of the Pack... Advantages of Packages The benefits of the Packages are as shown below: Modularity The Packages encapsulate logically associated items, types, and subprograms in the

Literals in pl/sql, Literals A literal is an explicit numeric, string... Literals A literal is an explicit numeric, string, character, or Boolean value not represented by an identifier. Numeric literal 147 and the Boolean literal FALSE are some of

Need fullcalendar modifications, Project Description: I am looking to ch... Project Description: I am looking to change FullCalendar to add/delete sql server data when events are removed or dropped from Calendar. Events should only be included by dra

Pass the nulls to a dynamic sql, Pass the nulls to a dynamic SQL: Pas... Pass the nulls to a dynamic SQL: Passing Nulls: Assume that you want to pass the nulls to a dynamic SQL statement. For illustration, you may write the EXECUTE IMMEDIATE

Using the collection methods, Using the Collection Methods The collecti... Using the Collection Methods The collection methods below help to generalize the code and make collections easier to use and also make your applications easier to maintain:

Execute privilege, EXECUTE Privilege To call an invoker-rights routine ... EXECUTE Privilege To call an invoker-rights routine straightforwardly, the users should have the EXECUTE privilege on that routine. By yielding the privilege, you permit a user