CREATE TABLE PROCEDURE

The CREATE TABLE PROCEDURE data description statement stores the definition of a table procedure in the SQL catalog. You can refer to the table procedure in SQL SELECT, INSERT, UPDATE and DELETE statements just as you would a table. These references result in CA IDMS calls to the corresponding external routine. Although such routines can perform any action, you use them typically to manipulate data stored in some other organization (for example, in a non-SQL-defined database or in a set of VSAM files).

You use the formal parameters of a table procedure definition like the columns of a table during a procedure invocation. You can input values in and return them from the table procedure using column-like syntax.

The CREATE TABLE PROCEDURE statement is a CA IDMS extension of the SQL standard.

Authorization

To issue a CREATE TABLE PROCEDURE statement, you must own the schema in which the table procedure is being defined or hold the CREATE privilege on the named table procedure.

Syntax

►►─── CREATE TABLE PROCEDURE ─┬───────────────┬─ table-procedure-identifier ──►
                              └─ schema-name. ┘

         ┌──────────── , ────────┐
 ►─── ( ─▼─ parameter-definition ┴ ) EXTERNAL NAME external-routine-name ─────►

 ►────┬─────────────────────────────────┬─┬──────────────────────────┬────────►
      └─── ESTIMATED ROWS row-count ────┘ └─ ESTIMATED IOS io-count ─┘
 ►────┬───────────────┬───────────────────────────────────────────────────────►
      ├─ USER MODE ◄──┤
      └─ SYSTEM MODE ─┘

 ►────┬──────────────────────────────────────┬────────────────────────────────►
      └─ LOCAL WORK AREA ── local-stge-size ─┘

 ►────┬────────────────────────────────────────────────────────┬──────────────►
      └─ GLOBAL WORK AREA ── global-stge-size ──┬──────────────┤
                                                └─ KEY key-id ─┘
 ►────┬───────────────────────────────────────────────────────────────┬───────►
      └─ TRANSACTION SHARING ───────────────────┬─ ON ───────┬────────┘
                                                ├─ OFF ──────┤
                                                └─ DEFAULT ◄─┘

 ►────┬───────────────────────────────────────────────────────────────┬───────►
      └─ DEFAULT DATABASE  ────────────────────┬ NULL ◄───┬───────────┘
                                               └─CURRENT──┘

 ►────┬───────────────────────────────────────────┬───────────────────────────►◄
      └── TIMESTAMP  timestamp-value ─────────────┘

Expansion of parameter-definition

►►─── parameter-name ── data-type ─┬────────────────┬─────────────────────────►◄
                                   └─ WITH DEFAULT ─┘

Parameters

table-procedure-identifier

Specifies the 1- to 18-character name of the table procedure you are creating. table-procedure-identifier must:

Be unique among the table, view, function, procedure and table procedure identifiers within the schema associated with the table procedure
Follow conventions for SQL identifiers

schema-name

Specifies the schema name qualifier to be associated with the table procedure. Schema-name must identify a schema defined in the dictionary. If you do not specify a schema-name, it defaults to:

The current schema associated with your SQL session, if the statement is specified through the Command Facility or executed dynamically
The schema associated with the access module used at runtime, if the statement is embedded in an application program

parameter-definition

Defines a parameter to be associated with the table procedure. Parameters are passed to the table procedure in the order they are specified. The list of parameters must be enclosed in parentheses. Multiple parameter definitions must be separated by commas.

Expanded syntax for parameter-definition is shown immediately following the CREATE TABLE PROCEDURE syntax. Descriptions for these parameters are located at the end of this section.

external-routine-name

Specifies the one- to eight-character name of the program which is called to process references to the table procedure.

row-count

Specifies an integer value, in the range 0 through 2,147,483,647, representing the average number of rows returned by the table procedure for a given set of input parameters.

io-count

Specifies an integer value, in the range 0 through 2,147,483,647, representing the average number of disk accesses generated by the table procedure for a given set of input parameters.

USER MODE

Specifies the table procedure should execute as a user-mode application program within CA IDMS. This is the default value unless SYSTEM MODE is specified.

SYSTEM MODE

Specifies the table procedure should execute as a system mode application program. To execute in system mode, the program must be fully reentrant and be written in either:

Assembler using DC calling conventions
COBOL or PL/I and compiled with an LE-compliant compiler

local-stge-size

Specifies an integer, in the range 0 through 32767, which represents the size, in bytes, of a local storage area which is allocated by CA IDMS at runtime and passed to the table procedure on each invocation.

CA IDMS allocates a local storage area on the first call to a table procedure for each SQL statement within a transaction or for a set of SQL statements which are related through reference to the same cursor (OPEN, FETCH, CLOSE, positioned UPDATE, and DELETE statements are related through a cursor). The same local storage area is passed to the table procedure for all calls for one statement or related statements. When the SQL statement has completed execution or when the cursor is closed, the local work area is released.

Note: If you do not code a LOCAL WORK AREA clause, the default local storage size is 1024 bytes.

global-stge-size

Specifies an integer, in the range 0 through 32767, representing the size, in bytes, of the global storage area that CA IDMS allocates at runtime and passes to the table procedure on each invocation.

CA IDMS allocates a global storage area once within a transaction and retains it until the transaction terminates.

key-id

Specifies the one- to four-character identifier for the global storage area. CA IDMS passes the same piece of global storage within a transaction to all SQL routines that have the same global storage key.

If you do not specify a storage key, CA IDMS allocates each table procedure its own global storage area, which is not used for any other routine within the transaction.

TRANSACTION SHARING

Specifies whether transaction sharing should be enabled for database sessions started by the table procedure. If transaction sharing is enabled for a procedure's database session, it will share the current SQL session's transaction.

ON: Specifies that transaction sharing should be enabled
OFF: Specifies that transaction sharing should be disabled.
DEFAULT: Specifies that the transaction sharing setting that is in effect when the table procedure is invoked should be retained.

DEFAULT DATABASE

Specifies whether a default database should be established for database sessions started by the table procedure.

NULL: Specifies that no default database should be established.
CURRENT: Specifies that the database to which the SQL session is connected should become the default for any database session started by the table procedure.

timestamp-value

Specifies the value of the synchronization stamp to be assigned to the table procedure. Timestamp-value must be a valid external representation of a timestamp.

Parameters for Expansion of parameter-definition

parameter-name

Specifies a 1- to 32-character name of a parameter to be passed to the table procedure. Parameter-name must:

Be unique within the table procedure that you are defining
Follow the conventions for SQL identifiers

All parameters are implicitly nullable. Input parameters can be assigned NULL as a parameter value and output parameters can return NULL.

data-type

Defines the data type for the named parameter. For expanded data-type syntax, see Expansion of Data-type.

WITH DEFAULT

Directs CA IDMS to pass a default value for the named parameter if no value for the parameter is specified.

The default value for a parameter is based on its data type:

Column data type	Default value
CHARACTER	Blanks
VARCHAR	A character string literal with a length of zero (that is, '')
GRAPHIC	Double-byte blanks
VARGRAPHIC	A double-byte character string literal with a length of zero
DATE	The value in the CURRENT DATE special register
TIME	The value in the CURRENT TIME special register
TIMESTAMP	The value in the CURRENT TIMESTAMP special register
All numeric data types	0 (zero)

Usage

Influencing Join Strategies

CA IDMS uses estimated row and I/O counts in determining the cost of joining a table procedure with other tables, views, or table procedures. To determine the optimal access strategy, CA IDMS examines different sequences for retrieving information. By providing the estimated row and I/O counts for the table procedure and for each access key used by the table procedure, CA IDMS can select the optimal access strategy.

In determining the cost of a specific access strategy, CA IDMS uses estimates provided in CREATE TABLE PROCEDURE unless input values are available for each of the parameters included in a key. If values are available for each of these parameters, CA IDMS uses the estimates specified in the CREATE KEY statement instead of those specified in CREATE TABLE PROCEDURE.

Specifying a Synchronization Stamp

When defining or altering a table procedure, you can specify a value for its synchronization stamp. You should use care when doing so because the purpose of the stamp is to enable the detection of discrepancies between an entity and its definition. If explicitly specified, you must set the synchronization stamp to a new value following a change so that the change is detectable by the runtime system.

If not specified, the synchronization stamp is automatically set to the current date and time.

Example

The following CREATE TABLE PROCEDURE statement defines a table procedure.

create table procedure emp.org
   (top_key          unsigned numeric(4),
   level             smallint,
   mgr_id            unsigned numeric(4),
   mgr_lname         char(25)
   emp_id            unsigned numeric (4),
   emp_lname         char(25)
   start_date        DATE,
   structure_code    char(2))
   external name procorgu
   local work area 800
   global work area 600 KEY EMP
   estimated rows 100
   estimated ios 50;

More Information

For more information about expanded table procedure references, see Expansion of Table-procedure-reference.
For more information about coding the external routine, see Defining and Using Table Procedures.
For more information about CREATE KEY, see CREATE KEY.