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All values in a column of a database table have the same data type. A value in a row of a column is the smallest data unit that can be selected from a table, to which functions can be applied and that can be modified. Each column in a base table has a name that is unique within the table.

Column Type



Character string column

All character strings in an alphanumeric column have the same length


Floating or fixed point column

All numbers in a floating point column have the same mantissa length

All numbers in a fixed point column have the same format, that is, the same number of pre- and post-point decimal places

Table 1: Columns


Description (Links to SQL Reference Manual)


Column Name (column_name)

Data Type

Data Type (data_type)



Maximum number of characters


Code attribute


If you select this option, you add this column to the primary key.

Key Definition (key_definition)

All columns in the primary key must be NOT NULL columns.

You cannot use any columns of the LOB data type in the primary key.

The database ensures that no NULL value exists in the key column and that no two data records in the table have the same values in all key columns.

Not Null

If you select this option, the value for this column cannot be a NULL value.

Column Attributes (column_attributes)


Default value

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