Relational Data Framework Reference › SQL Statements › ALTER TABLE Statement—Add a Table Column

ALTER TABLE Statement—Add a Table Column

An ALTER TABLE statement, issued with an ADD COLUMN clause, is used to add a column to an existing relational table. A table can contain up to 100 columns.

Note: You can use host variables for tablename and colname.

• Use this syntax in an AOF rule or an OPS/REXX program:

  ADDRESS SQL "ALTER TABLE keywords" {tablename}
    ADD COLUMN
    {colname}
    {datatype}
    [DEFAULT string|NULL]
    [UPPER CASE]
    [NOT NULL]
    [SYSTEM(ALL|EXT|sysnames)]
    [SYSWAIT(seconds)]
    [OUTPUT|NOOUTPUT]
    [SYSPLEX]
  

• Use this syntax to invoke the statement from a TSO terminal, a TSO/E REXX program, or a TSO CLIST:

  OPSQL ALTER TABLE {tablename}
    ADD COLUMN
    {colname}
    {datatype}
    [DEFAULT 'string'|NULL]
    [UPPER CASE]
    [NOT NULL]
  

tablename

Defines the 1- to 18-character name of the relational table to which you are adding a column.

colname

Defines the 1- to 18-character name of the column that you are adding.

datatype

Defines the type of data the column will store.

Data types include:

• CHAR(length)-Character data, with length as the fixed number of characters you want this column to store.

  Note: We recommend using data type CHAR for most purposes, or VARCHAR if the length of the stored data differs from row to row and the full potential length of the column is seldom used. CHAR and VARCHAR are processed more efficiently than other data types.

• DATE-A date indicator of the form yyyy-mm-dd; for example, 1994-07-25.
• DECIMAL-Decimal data, with the maximum number of digits being 15.
• HEX(length)-Hexadecimal data, with length as the maximum number of hexadecimal bytes this column will store.
• INTEGER-Full-word integer data, with a maximum value of 2147483647.
• SMALLINT-Half-word integer data, with a maximum value of 32767.
• TIME(length)-A time indicator of the form hh:mm:ss.nnn; for example, 13:21:53.876. If a value for length is not specified, then the default value of 8 is used.
• TIMESTAMP(length)-A date/time indicator, the format being a combination of the DATE and TIME formats. If a value for length is not specified, then the default value of 20 is used.
• VARCHAR(length)-Character data, with length as the maximum number of characters this column will store.

Notes:

• Data of type CHAR is stored in fixed lengths by RDF and padded, as necessary, with blank characters. Data of type VARCHAR is stored in variable lengths by RDF and not padded. Use of the VARCHAR data type saves space in the CA OPS/MVS global variable pool when it is used to store data that is often significantly less than the maximum defined length of a column. VARCHAR data types cannot be defined as primary keys because of their variable length values.
• The DATE, TIME, and TIMESTAMP data types are stored as unsigned packed decimal numbers. When you are inserting, updating, deleting, or searching for values of these types, you must specify the data type along with the value. For example:

  WHERE UPDATE = DATE '1994-04-27'

DEFAULT string

(Optional) Indicates the string is a default value to be set for this column if an INSERT statement does not provide a data value. The default string can be either a character string or a numeric string. If you are using the OPSQL command processor to invoke the ALTER TABLE statement, you must enclose the value of string in single quotes.

NULL

(Optional) Indicates that the column can contain no data. This is the default.

UPPER CASE

(Optional) The UPPER CASE keyword in a column definition specifies that the column can contain only uppercase characters. It also instructs SQL to convert any lowercase value inserted into that column to uppercase.

NOT NULL

(Optional) Indicates that the new column cannot contain a null data value.

SYSTEM

(Optional) Performs cross-system SQL operations. Specify one of the following values:

ALL

Routes the SQL command to all active MSF-defined systems, including the local system.

EXT

Routes the SQL command to all remote, active MSF-defined systems.

sysnames

Routes the SQL command to the specified systems. You may specify from one to eight system names as the value of sysnames.

For more information, see the chapter “Using the Relational Data Framework” in the User Guide.

SYSWAIT

(Optional) Defines the number of seconds the SQL processor waits for output from a remote system. You may specify a value between 1 and 300 seconds.

Do not specify a value for SYSWAIT if you specify the SYSTEM(ALL), SYSTEM(EXT), or NOOUTPUT keywords.

OUTPUT or NOOUTPUT

(Optional) Indicates whether the command returns output to the external data queue. Specify OUTPUT to have output returned; otherwise, specify NOOUTPUT.

NOOUTPUT is implied when:

• The ADDRESS SQL command is issued in an AOF rule.
• You specify more than one system name as the value of the SYSTEM(sysnames) keyword.
• You specify SYSTEM(ALL) or SYSTEM(EXT).

SYSPLEX

(Optional) Reduces the scope of the SYSTEM(ALL|EXT) operand to MSF connected systems that belong to the same z/OS sysplex as the command issuer. The keyword has no effect on a list of explicit system names.

Example: Add a Table Column

Add an eight-character column called OPERNAME

ADDRESS SQL
  "ALTER TABLE SYSTEMS ADD COLUMN OPERNAME CHAR(8) NOT NULL"