SQL ALTER TABLE statement gives options to change almost every thing in TABLE structure. SQL: ALTER TABLE Statement This SQL tutorial explains how to use the SQL ALTER TABLE statement to add a column, modify a column, drop a column, rename a column or rename a table (with lots of clear, concise examples). The table is a system-period temporal table. db2 runstats on table fruit and indexes all If you will alter the varchar(n) column to varchar(n +x), it is the only situation that you don't need to reorg your table. ALTER statement we can use in DB2 SQL query to drop a column. To do this in SQL, we specify that we want to change the structure of the table using the ALTER TABLE command, followed by a command that tells the relational database that we want to rename the column. ALTER TABLE DEPT DROP COLUMN NUMDEPT. When an ALTER TABLE RENAME COLUMN command runs on the system, DB2 will rename the column in the table and invalidate the dependent objects (if any) such as views, functions, procedures, materialized query tables (MQT), and so on.
The exact syntax for each database is as follows:
It was a small table at less than 1,000 rows, and I wanted to be able to experience and decide based on having done both on a test table. Like Add, Drop or Change definition of column(s). The table structure looked like this: SQL > ALTER TABLE > Rename Column Syntax. The table is a created global temporary table. We've also added some … ALTER TABLE table_name DROP COLUMN column_name. The containing table space is not a universal table space. Invalidated objects would get validated when the dependent objects are being accessed within the application or outside the application by a user. Alter the table to change the data type of the column; Use ADMIN_MOVE_TABLE to change the data type of the column; I tested both solutions on a dummy copy of the table. Changing a column Posted: Thu Sep 13, 2007 6:05 pm Post subject: DB2 Alter Table command - default value Hi, I am trying to run the following DB2 command to alter a column to set its default value as given below. But, there are lot other conditions involved, which column we can drop or not.
subject: [db2-l] alter column length db2 v8; i just want to alter the length of a column, all attributes remain the same decimal (9) to decimal (17,4) alter table alter column xyx_xyz set data type decimal(17,4) ; would this work? Adding a column. Sometimes we want to change the name of a column. ALTER TABLE clients ALTER COLUMN phone NVARCHAR (20) NOT NULL; Verify Altered Nullability Once the alteration to your column is made, it is a good practice to verify the column no longer allows any NULL values by running a simple INSERT test and trying to insert a new record with the NULL value in the altered column: