robf@squid.rtech.com (Robert Fair) (08/03/90)
Ingres 6.x SQL *does* handle view definitions containing UNION and UNION ALL, e.g. CREATE VIEW a_and_b AS SELECT x FROM a UNION SELECT x FROM b works just fine. Robert Fair Premium Support Group Ingres Corporation, NJ Standard disclaimer applies.
gordon@mead.UUCP (Gordon Edwards) (08/03/90)
In article <5670@rtech.Ingres.COM>, robf@squid.rtech.com (Robert Fair) writes: |> Ingres 6.x SQL *does* handle view definitions containing UNION and UNION ALL, |> e.g. |> CREATE VIEW a_and_b |> AS |> SELECT x FROM a |> UNION |> SELECT x FROM b |> |> works just fine. |> No one is questioning the ability to create a view containing a UNION. Can the view be updated is the question. ---- 1) ANSI says, "Just say no." (ANSI X3.135-1989 pages 53, 66, 79) <view definition> ::= CREATE VIEW <table name> [(<view column list>)] AS <query specification> [WITH CHECK OPTION] Syntax Rule 3) If the <query specification> is updatable, then the viewed table is an updatable table. Otherwise, it is a read-only table. <query expression> ::= <query term> | <query expression> UNION [ALL] <query term> <query term> ::= <query specification> | (<query expression>) <query specification> ::= SELECT [ALL | DISTINCT] <select list> <table expression> <select list) ::= <value expression> [{, <value expression>}...] | * ---- 2) My previous post argues the case from a logical point of view. To be updatable, the INSERT, UPDATE, and DELETE operations have to be defined. If the view is created with a UNION, which table will a tuple be inserted? Ingres can't update a view created with a UNION! I tried using Ingres 6.3, and it came back and told me that the update was illegal. INSERT INTO v1 VALUES (10, 10) returned... E_US0D21 INSERT on view v1: cannot update this view.) (Fri Aug 3 09:31:55 1990) ---- I made a subtle error in my previous post on this thread. I said that neither Ingres or *SYBASE* supports this feature. Sybase doesn't support views at all in the current release (yes, I know it's going to be fixed). ---- Gordon Edwards Mead Data Central, Dayton OH Please, post responses. Our mail feed will be changing any day now, and my e-mail address may not work.
jeffl@sybase.Sybase.COM (Jeff Lichtman) (08/06/90)
> Sybase doesn't support views at all > in the current release (yes, I know it's going to be fixed). No, it's unions that Sybase doesn't support. Sybase has always supported views, and will support unions starting with release 4.2, which will be available in production soon. --- Jeff Lichtman at Sybase {mtxinu,pacbell}!sybase!jeffl -or- jeffl@sybase.com "Saints should always be judged guilty until they are proved innocent..."
gordon@mead.UUCP (Gordon Edwards) (08/10/90)
In article <10420@sybase.sybase.com>, jeffl@sybase.Sybase.COM (Jeff Lichtman) writes: |> > Sybase doesn't support views at all |> > in the current release (yes, I know it's going to be fixed). |> |> No, it's unions that Sybase doesn't support. Sybase has always supported |> views, and will support unions starting with release 4.2, which will be |> available in production soon. OOPS!!! I was typing ahead of my brain again. I have even used views in Sybase before. Looks like I need more help than your typical spell checker can provide. Sorry. -- Gordon Edwards Mead Data Central, Dayton OH Please, post responses. Our mail feed will be changing any day now, and my e-mail address may not work.