Displays the name currently specified for the column that you are altering. You cannot alter this field for an existing column. To specify a different name for a column that you are adding, type the new name for the column in this field. This name can contain up to 30 characters and be an ordinary or delimited identifier.

Attention: You cannot use the same name for more than one column of the table.

Contains the data type currently specified for the column. You cannot alter this box for an existing column. To specify a different data type for a column that you are adding, click the down arrow to display a list of data types and select one.

Displays the length currently specified for the column.

Contains the LOB unit currently specified for the column. You cannot alter this box for an existing column.

Displays the precision currently specified for the column of data type DECIMAL. You cannot alter this field for an existing column. To change the precision for a column that you are adding, type a new value in this field. The precision is the total number of digits in a DECIMAL number, which can range from 1 to 31. If you do not specify the precision, a default value of 5 is used.

This field is available only if you specified DECIMAL in the Data type box and only for a new column.

Displays the scale currently specified for the column of data type DECIMAL. You cannot alter this field for an existing column. To change the scale for a column that you are adding, type a new value in this field. The scale is the number of digits to the right of the decimal point, which can range from 0 to the precision of the number. If you do not specify the scale, a default value of 0 is used.

This field is available only if you specified DECIMAL in the Data type box and only for a new column.

Specifies that the column contents are not generated by the DB2 engine

Specifies that changes made to the column are written to the log. The data is then recoverable with database utilities, such as RESTORE DATABASE.

Note: LOBs greater than 1 GB cannot be logged, and LOBs greater than 10 MB should not be logged for performance reasons.

This is available for new columns of data type BLOB, CLOB, DBCLOB, or a distinct type with any of these as source types in the Data type box. You cannot alter this check box for an existing column.

Specifies that the values in the LOB column should take up minimal disk space. This is available for new columns of data type of BLOB, CLOB, DBCLOB, or a distinct type with any of these as source types in the Data type box. You cannot alter this check box for an existing column.

Note: Storing data in this way can cause a performance penalty in any append (length-increasing) operations on the column.

Displays the current check box specified for the column. You cannot alter this check box for an existing column. For a column that you are adding, you can select or clear this check box to change the setting. If you select this check box, the contents of the column will be treated as bit (binary) data. During data exchange with other systems, code page conversions are not performed. Comparisons are done in binary, irrespective of the database collating sequence.

This check box is available only if you specified a data type of CHARACTER, VARCHAR, or LONG VARCHAR in the Data type box and only for a new column.

Specifies that you want to use a default value for a column. The Default entry field shows the value.

Displays the default value currently specified for the column. To change the default value for a column, select the radio button, then type the constant value, CURRENT DATE, CURRENT TIME, CURRENT TIMESTAMP, USER, or NULL in this field. Ensure that the expression is valid for the Datatype characteristics that you specified.

The default value you type will be used exactly as entered, so you must make sure that the value is properly delimited. For example, default literals for a CHAR or VARCHAR column should be delimited with single quotes.

Optional: Select to have minimal disk space usage if the inserted/updated value is equal to the system default value for the data type of the column. This option works for all numerical type columns and fixed-length character/graphic strings. When selected, value compression is automatically selected for the entire table.

Shows if DB2 automatically generates the contents of the column. DB2 uses a formula when it generates the values for the generated column. The contents are dynamically updated if any dependencies change.

Displays the formula used when generating the values for the generated column.

Ensure that the expression is valid for the Datatype characteristics that you specified.

Shows if the generated column is an identity column. DB2 generates a unique numeric value for each row in the table. The data type of the column must be SMALLINT, INTEGER, BIGINT, or DECIMAL(n,0) and the column cannot be NULL.

Specifies the first value in the identity column.

Displays the incremental number that DB2 uses when it generates a number for each row.

Specifies the number of identity column values that you want to be cached. This allows DB2 to cache identity column values to obtain better performance for applications.

Allows the column to contain null values. The default value for the column is either the null value or, if the Default radio button is checked, the value specified in the Default field.

Attention: If the column will be a primary key column, it cannot be nullable.

Optional: Contains the comment currently specified for the column. To change the comment, type the new comment in this field. You can type up to 254 characters, including embedded blanks.

Allows DB2 to automatically generate the contents of the column.

Displays the name currently specified for the column that you are altering. You cannot alter this field for an existing column. To specify a different name for a column that you are adding, type the new name for the column in this field. This name can contain up to 30 characters and can be an ordinary or delimited identifier.

Attention: You cannot use the same name for more than one column of the table.