DB2 gives us an option of modifying the attribute of the existing column in a table. We have to use the ALTER COLUMN parameter with ALTER TABLE as below in order to achieve this.ALTER TABLE DBSET1.TAB1    ALTER COLUMN NAME       SET DATATYPE CHAR(50);The ALTER TABLE reserved words ... Read More

DB2 gives us an option to copy the structure of an existing table to a new table. To copy the attributes and column of table TAB1 to a new table TAB2 we can use the following command−CREATE TABLE DBSET1.TAB2    LIKE DBSET1.TAB1The CREATE TABLE reserved words are followed by table ... Read More

A view is an alternative way of representing the data stored in a table. A view can be used to increase the performance of the query since the view contains very limited rows as compared to its source table. We can use the below command to create a view on ... Read More

A foreign key is a column in a table that establishes a referential link with another table. A foreign key can be defined during creation of table (CREATE TABLE command) or it can be defined by modifying the table (ALTER TABLE command). However, before defining any key as foreign key, ... Read More

We can add a new column in an existing table as per the business requirements. Similarly, we can also remove a column from the table. This could be done using the ALTER table command as below.ALTER TABLE TAB1 ADD COLUMN ADDRESS VARCHAR(100);The ALTER TABLE reserved words are followed by the ... Read More

Constraints are used to restrict the data inserted at a particular column. Constraints can be used in such a way that a value can only be inserted if it satisfies the condition given in constraints. We can give the below parameter during CREATE TABLE command to add a constraint.CREATE TABLE ... Read More

An index is a lookup table that optimizes the searching of data. An index defined on any table can increase the query speed. The index can be built up on any column of the table and DB2 will generate a logical structure at backend. This will facilitate the search on ... Read More

A table is a logical structure of a data in a DB2. A table consists of a column which represents the attribute and rows represents the entity. Below command can be issued in order to create a new DB2 table.CREATE TABLE DBSET1.TAB1    (STUDENT_ID CHAR(10) NOT NULL,    ENROLLMENT_ID CHAR(20) ... Read More

A Volume is a group of physical disks which are used to store the data. A storage group is a collection of volumes. We can add or remove the volumes in a storage group in order to adjust the space. Below command can be issued in order to amend the ... Read More

Bufferpool is the unit of the main memory which is used to cache the data in the DB2 table. The data is stored in the cache once the database manager reads the data from the disk to the main memory. The bufferpool can be defined by giving the pagesize.The page ... Read More