Define Db2 LUW Domain Properties

In a model based on a Db2 for LUW target server, you use the Db2 for LUW tab in the Domain Editor to manage the data type, null option, and other properties for the selected domain.

The options described here are the basic options available for most physical data types. There can be more options available depending on the physical data type you assign to the domain. We recommend that you refer to IBM Db2 for LUW documentation for more information about using these properties.

To specify Db2 for LUW domain properties

1. Click Domains on the Model menu.

   The Domain Editor opens.

2. Select the domain in the Navigation Grid that you want to define.

   Click New on the toolbar to create a new domain. Use the Enter filter text text box to filter a very large list of domains to quickly locate the one that you want to define.

3. Click the Db2 for LUW tab and work with the following options:

   Physical Data type

   Lets you select a data type from the drop-down list to apply to the selected domain. If the selected data type requires a value for precision, scale, or both, enter the value inside the data type parentheses. For example, you can select the DECIMAL() data type and specify a precision of 2 and a scale of 10 inside the parentheses to assign the data type DECIMAL(2,10) to the selected domain.

   Character Type

   Lets you specify the data subtype for character columns. Select a value from the drop-down list.

   This option is only available if you select either the CHAR, CHAR(), CHARACTER, CHARACTER(), VARCHAR(), or LONG VARCHAR() data type.

   Maximum Length In Row

   Lets you enter the maximum length allowed in a row for the data type you assigned.

   Null Option

   Lets you specify a null option.

   Average Width

   Lets you enter an estimated average width for columns if variable width is allowed based on the data type you assigned. If it is not allowed, an error is displayed in the Details section at the bottom of the editor. You can later use the Volumetrics dialog to calculate table and database size estimates based on these and other values.

   Percent Null

   Lets you enter the estimated percentage of nulls used for columns if the option is available. Use whole numbers. You can later use the Volumetrics dialog to calculate table and database size estimates based on these and other values.

   Security Label

   Specifies the security label to apply to the domain. Select a security label from the drop-down. You can also use the drop-down to open the Db2 for LUW Security Label Editor to work with security labels. Security labels are associated with security label components to define a security policy.

   Column Compression

   Specifies whether to use column compression. Select the check box to enable this option.

   Is LOB Data Compacted

   Specifies whether the LOB data in a LOB column is compacted.

   Is LOB Data Logged

   Specifies whether updates to a LOB column are recorded in the system log.

   Generated

   Specifies how Db2 generates values for a column. This field is not available for the Blob data type.

   Generated Expression

   Lets you enter the expression that specifies the column definition. This field is not available for the Blob data type.

   Is Row Change Timestamp Column

   Specifies the ROW CHANGE TIMESTAMP column specification. Select the check box to enable this option. This field is available only for the Datetime data type.

   Is Implicitly Hidden

   Specifies the IMPLICITLY HIDDEN column specification. Select the check box to enable this option. When this option is enabled, the column is not visible in SQL statement results unless it is explicitly referred to by name. This field is available only for the Datetime data type.

   The following fields are available only for the Number data type.

   Generated Identity

   Specifies whether or not the column is the identity column for the selected table.

   Starting Value

   Specifies the first value for the identity column.

   Increment By

   Specifies the interval between consecutive values of the identity column.

   No Minimum Value

   Specifies whether or not there is a minimum value for the identity column sequence.

   Minimum Value

   Specifies the minimum value for the identity column sequence.

   No Maximum Value

   Specifies whether or not there is a maximum value for the identity column sequence.

   Maximum Value

   Specifies the maximum value for the identity column sequence.

   Cycle Values

   Specifies whether or not the identity column should continue to generate values after generating either the maximum or minimum value.

   Cache Values

   Specifies whether or not to keep some pre-allocated values in memory for faster access.

   Cache Capacity

   Specifies the number of values of the identity column sequence that Db2 LUW can preallocate and keep in memory.

   Order Values

   Specifies whether or not the values of the identity column sequence are generated in order of request.

4. Click Close.

   Domain properties are defined and the Domain Editor closes.