SQL Anywhere Studio Help
Adaptive Server Anywhere Help
Introduction to property sheets
Column property sheet
The Value tab of the Column property sheet has the following components:
No default or computed value Select this option if the column is not a computed value and has no default value.
Default value Select this option if the column has a default value. If the column is based on a domain, this setting inherits the domain's default value (if any), but the value can be overridden for the column. Choosing the Default Value option enables the User-defined and System defined options.
User-defined Lets you type a custom value (string, number, or other expression) for the default value. If you've based the column on a domain, you can retain the domain's default value (if any) or override it for the column.
System-defined Lets you select a pre-defined value (for example, current date) for the default value. You must select a value from the dropdown list. If you have based the column on a domain, you can retain the domain's default value (if any) or override it for the column.
Partition size When you select global autoincrement for the system-defined value, you can also supply a partition size.
Global autoincrement assigns each new row a value of one greater than the previous highest value in the column. The partition size restricts the maximum value that global autoincrement can use. You can enter any positive integer for the partition size. Generally, you should select a value so that the supply of numbers is rarely, if ever, exhausted.
For more information, see The AUTOINCREMENT default and CREATE TABLE statement.
Computed value Select this option to define a computed value for the column. A computed column derives its values from calculations of values in other columns. Type an expression in the text box to describe the relationship between the other columns and the value that appears in the computed column.
For more information about computed values, see ALTER TABLE statement and Subqueries in expressions.