HP 3000 Manuals

Up and Running with ALLBASE/SQL

Examining the System Catalog 

Whenever you create objects in ALLBASE/SQL, their characteristics are
stored in the system catalog, which is a special system-created database.
The system catalog is like a listing of the contents of a DBEnvironment.
(See the illustration below.)


            

You can look at the system catalog by performing queries on system 
tables.  Issue the following query to see entries for the tables and
views you have just created:

     isql=> SELECT * FROM SYSTEM.TABLE Return 
     > WHERE OWNER = USER; Return 

The next figure shows the first display you see.
____________________________________________________________________________________
|                                                                                  |
|                                                                                  |
|      select * from system.table where owner = USER;                              |
|      --------------------+--------------------+--------------------+------+----- |
|      NAME                |OWNER               |DBEFILESET          |TYPE  |RTYPE |
|      --------------------+--------------------+--------------------+------+----- |
|      ALBUMS              |PETERW              |ALBUMFS             |     0|      |
|      SELECTIONS          |PETERW              |SYSTEM              |     1|      |
|      TITLES              |PETERW              |ALBUMFS             |     0|      |
|                                                                                  |
|                                                                                  |
|                                                                                  |
|                                                                                  |
|                                                                                  |
|                                                                                  |
|                                                                                  |
|                                                                                  |
|                                                                                  |
|                                                                                  |
|                                                                                  |
|                                                                                  |
|      --------------------------------------------------------------------------- |
|      Number of rows selected is 3                                                |
|      U[p], d[own], l[eft], r[ight], t[op], b[ottom], pr[int] <n>, or e[nd] > e   |
|                                                                                  |
|      isql=>                                                                      |
|                                                                                  |
____________________________________________________________________________________

          Figure 3-2.  System.Table Display 

Enter "r" to scroll right to see all the columns.  A complete description
of each column appears in chapter 9 of the ALLBASE/SQL Database 
Administration Guide.  For now, notice the value in the TYPE column.  A
zero (0) indicates a table, a one (1) indicates a view.

Updating Statistics in the System Catalog 

Use the UPDATE STATISTICS command for each table as follows:

     isql=> UPDATE STATISTICS FOR TABLE ALBUMS; 
     isql=> UPDATE STATISTICS FOR TABLE TITLES; 

This ensures that the current number of rows in each table and other
statistical information are updated in the system catalog.  The
statistical information is used by SQLCore when it decides whether to use
an index or not.  Statistics also provide information about ongoing
processes within the DBEnvironment.

MPE/iX 5.0 Documentation