Re: add constraints to views

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Gaetano Mendola wrote:
| Andreas Fromm wrote:
|
|> CREATE VIEW test_view (
|> ~    SELECT * FROM test_table WHERE tag
|> );
|>
|> Now I want ad a NOT NULL constraint to the view on field1. I tryed the
|> following, but neither works.
|
|
| what does mean add a null constrain to a view ?  Do you mean
| filter out the records with the field1 null ?
|
| CREATE OR REPLACE test_view AS
|     SELECT *
|     FROM test_table
|     WHERE field1 IS NOT NULL AND
|           tag;
|
No, I mean that the view behaves like a table with the same columns as
table, but that restricts to records on wich tag is set. To insert a
record to this "special"  table it requires to have field1 set. In other
words: A record of table is a record of view if tag is set. If tag is
set, then field1 has also have to have a value. If tag is not set, it
may have a value for field1, but will not show up in the view. Of course
I could achive this be triggers, but I thought it could be possible to
do via constraints on the view.

Regards

Andreas
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