Getting Started with IBM Data Studio for DB2

Chapter 2 – Managing your database environment 83
Field
Primary Key
Data Type
Length
Scale
Not Null
Generated
Default
Value/Generate
d Expression
Description
Click this box if you want this column to be the primary key for the
table.
Data type of the column. Click in the field to activate it for editing and
then open the pull down menu to see all the data types supported in
the drop down menu.
The length of the column. For some of the data types it is fixed and in
those cases you cannot edit this.
Specify the scale for the column type wherever applicable. Again, if it’s
not applicable to this data type, you won’t be able to edit this.
Click the box if the column value cannot be null. This option is
automatically selected for primary key columns, because primary keys
are not allowed to be null.
Click this box if you want the DB2 system to automatically generate
the value of this column based on a default value or expression that
you provide.
If the Generated box is selected, you need to specify a default value or
an expression that the DB2 system will evaluate to generate the value
of this column whenever a value is not specified in theINSERT
statement. For example a total salary column can be the sum of basic
salary (column namebasicSalary) and allowances (column name
allowances). You can specify forsalaryColumn as Generated
expression ofbasicSalary + allowances
Table 2.2 – Column details
In the planned changes bar of the object list editor, you will see the count of changed
objects update to include the new table. In Section 2.4.5, you will deploy the new table to
the database with other objects in a change plan.
2.4.3 Creating indexes
To create an index on a column of the table:
Right-click the Indexes folder in the Administration Explorer and select Create Index.
You must specify what table will use this index. Expand theMYSCHEMA node and select
theMYTABLE table, as shown in Figure 2.17, and click OK. The Properties view for the
new index opens.