TABLES: Alter Table notebook -- Infopops

Shows the columns defined for the table that you are altering. You can view your column definitions or select a column to change or remove.

You can add a new column, remove an existing column or change an existing column's attributes such as data type, length, precision or scale by directly editing the values in the cell. If you add a new column, you can select the new column and change any field, remove the new column from the table, or reorder the new column among other new columns. Click Add to add a column to the list. Make each column name in the table unique. The name can be 1 - 128 characters and have either an ordinary or delimited identifier

Click on a cell to enter a value directly.

Opens a window in which you can add a new column to the table that you are altering.

You can add up to 500 columns to your table. The sum of the byte counts of the columns must not be greater than 4005.

Opens a window in which you can change any attributes of a column selected in the Columns table. The existing data in the table must conform to any new constraints defined for the table columns. For example, if a nullable column is changed to be not nullable, an error will be returned by the alter process if the data in this column contains any null values.

Any field in any column can be changed. If you make a change that requires the Control Center to drop and re-create the table, a warning will be displayed.

Immediately removes any new columns that you added.

Does not remove existing columns, but places them in remove pending state. The columns are removed when the alter table operation is performed. The remove operation can be undone prior to submission of the alter table request.

Opens a window in which you can select a predefined column to add to the table.

Moves the selected column up one position. You can only reorder new columns among other new columns. You cannot reorder existing columns.

Moves a selected column down one position. You can only reorder new columns among other new columns. You cannot reorder existing columns.

Opens a window in which you can view objects affected by altering the table.

Shows the columns defined for the table that you are altering. You can view your column definitions or select a column that you want to change, remove, or reorder.

You can select an existing column and change the comment or the length of a VARCHAR data type. If you add a new column, you can select the new column and change any field, remove the new column from the table, or reorder the new column among other new columns. Click Add to add a column to this list. Make each column name in the table unique. The name can be 1 - 30 characters and have either an ordinary or delimited identifier

Opens a window in which you can add a new column to the table that you are altering.

You can add up to 500 columns to your table. The sum of the byte counts of the columns must not be greater than 4005.

Opens a window in which you can change an attribute of a column selected in the Columns table. You can change the comment for an existing column, or change any field for a new column that you are adding.

Removes a selected column from the table. You can only remove new columns that you added, not existing columns.

Opens a window in which you can select a predefined column to add to the table.

Moves the selected column up one position. You can only reorder new columns among other new columns. You cannot reorder existing columns.

Moves a selected column down one position. You can only reorder new columns among other new columns. You cannot reorder existing columns.

Shows the constraint name for the columns defined as keys in the table.

Shows the type of the key. The key type can be primary, unique, foreign, or distribution. (Distribution keys are for partitioned databases only.) Only one unique key can be defined as the primary key.

Shows the key columns in the table.

Opens a window in which you can add a primary key column. You can define only one primary key.

Opens a window in which you can add unique key columns.

Opens a window where you can add foreign key columns.

Opens a window in which you can add distribution key columns (for partitioned databases only).

Removes the selected key.

Opens a window in which you can change a selected key.

Shows the dimension numbers assigned by the system. Dimension numbers are integers, starting at 1. The system does not generate or store dimension numbers in the catalogs.

Shows the columns in the column group defined in a specific dimension.

Shows the check constraints defined for the table. You can change or remove an existing check constraint, or add a new check constraint using the Add button.

Shows the status of a column.

Shows the check conditions specified for a check constraint.

Shows any comments entered for a check constraint.

Opens a window in which you can add a new check constraint to the table.

Opens a window in which you can change an attribute of a selected check constraint.

Removes a selected check constraint from the table.

Shows the name of the schema specified for the table. You cannot alter the schema.

Shows the name currently specified for the table. To specify a different name, use the Rename Table window. You cannot alter the table name using the Alter Table notebook.

Shows the name of the table space in which the table was created. You cannot alter the table space.

Shows the name of the table space in which any indexes on the table were created. You cannot alter the index table space.

Shows the name of the table space in which the values of any long columns are stored. Long data can be LONG VARCHAR, LONG VARGRAPHIC, LOB data types, or distinct types with any of these as source types. You cannot alter the long data table space.

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

Shows the size (granularity) of locks used when the table is accessed. To change the lock size, click the down arrow to display the list and select a value.

ROW Indicates the use of row locks. This is the default lock size when the table is created.

TABLE Indicates the use of table locks. With table locks, the appropriate share, update, or exclusive lock is acquired and intent locks (except intent none) are not used.

Table locks may improve the performance of some queries by limiting the number of locks to be acquired, however, concurrency is also reduced because all locks are held over the complete table.

Use of the Lock size control will not prevent normal lock escalation from occurring.

Specify one of the following:

Specify the percentage of each page to leave as free space during a load or reorganization process.

The first row on each page is added without restriction. When additional rows are added, the value specified in this field determines the percentage of free space left on each page.

Select a percent from 0 to 99.

Select to indicate whether extra information regarding SQL changes to this table are to be written to the log. This additional information is required if this table will be replicated. This check box must be selected if you plan to use this table as a source for replication.

Indicates whether long varchar and long vargraphic column information for the table will be written to the log during data capture for propagation.

Select to enable a long field log record that includes long varchar and long vargraphic columns in the log. If you select this check box for tables that do not have long variable length columns now, you can alter a table later to include long variable length columns.

Indicates whether data is appended to the end of the table data or placed where free space is available in data pages.

Indicates to the optimizer that the cardinality of your table can vary significantly at run time from empty to quite large. Therefore, when accessing your table, the optimizer will use an index scan rather than a table scan, regardless of the statistics, if the index is index-only (all columns referenced are in the index) or the index is able to apply a predicate in the index scan.

If this box is cleared, access plans to this table will be based on the existing statistics and on the defined optimization level.