Views in DB2
Creating views can improve query response times by restricting the number of tables and columns searched when a data request is made. You can create views that appear to client applications as feature classes or nonspatial tables. An ArcSDE view can reference a single table or feature class, or you can create views to join data from multiple tables.
Any user that has the required permissions can create a view using SQL or the ArcSDE sdetable command. Additionally, views can be used to edit data if the view is created to allow edits. For information on privileges needed to create or edit views, consult the IBM DB2 Information Center for your release.
View definitions can be accessed through the SYSCAT.VIEWS system catalog view in DB2 databases.
SYSCAT.VIEWS shows view information
When you create views in DB2 using SQL or the sdetable command, they are stored in DB2 system tables. Rather than access the system tables, though, query the DB2 system catalog view SYSCAT.VIEWS to see view definitions. SYSCAT.VIEWS contains one or more rows for each view created.
|
Field name |
Data type |
Description |
|---|---|---|
|
VIEWSCHEMA |
VARCHAR(128) |
Along with VIEWNAME, the qualified name of a view or table that is used to define a materialized query table or staging table |
|
VIEWNAME |
VARCHAR(128) |
Along with VIEWSCHEMA, the qualified name of a view or table that is used to define a materialized query table or staging table |
|
DEFINER |
VARCHAR(128) |
Authorization ID of the creator of the view |
|
SEQNO |
SMALLINT |
Always 1 |
|
VIEWCHECK |
CHAR(1) |
The type of view checking
|
|
READONLY |
CHAR(1) |
Y = Read-only view because of its definition or N = Not read-only view |
|
VALID |
CHAR(1) |
Y = Valid view or materialized query table definition valid or X = Inoperative view or materialized query table definition; must be re-created |
|
QUALIFIER |
VARCHAR(128) |
Contains value of the default schema at the time of object definition |
|
FUNC_PATH |
VARCHAR(254) |
The SQL path of the view creator at the time the view was defined When the view is used in data manipulation statements, this path must be used to resolve function calls in the view. (Use SYSIBM for views created before version 2.) |
|
TEXT |
CLOB(64K) |
Text of the CREATE VIEW statement |