Practical Use of Views

[marcon]

I am a beginner and am writing procedures that will create a view once a month with around 2-5 mil records. This view will be used to consolidate data into smaller tables. Is there a rule of thumb based on "common practices" that I can use in deciding if a table should be created instead of a view?
Let me put it another way.. when do you NOT use views in place of a table?
Any "views" greatly appreciated.

 

[lfoata]

Views are based on tables, it aquires the data from tables and format it a different way. Too bad I.T. is not cash business

Luc Foata
Unix sysadmin, Oracle DBA

 

[marcon]

Thanks for the response. I'm sorry I was not clear. From a resource standpoint, when is it impractical to use a view? For example , if a query is based on views, is there a point where the queries should be based on tables to save time? Any general guidelines?

 

[oracle8]

Marcon,

Views are made to simplify query. Meaning, if you have a query joining 3 or more tables create a view to simplify everything and does make your query faster. Hope this help...


Oracle8

 

[jimbopalmer]

In my experience, making views containing other views will confuse the optimizer and result in slow execution of your queries. The one thing you can't give for your heart's desire is your heart. - Lois McMaster Bujold

 

[sem]

The main advantage of views was in that they were stored compiled so you may use some time on parsing stage. Bust since Oracle 8 their functionality was significantly improved. You may create triggers to update tables the view is based on. You may also create snapshots, called now "Materialized Views". According to your task I suppose you use materialized views. Normally they are used to eliminate the need in repeating heavy operations, returning the same result (quasy-static). If you have a big table or aset of tables and want to base your queries on some intemediate agregations you may create materialized view that is just a temporary table, storing the agregations you need. Your initial table may contain milions of records but materialized view - only hundreds. You may refresh this materialized view on a regular basis.