The Natives are getting restless, an overview of DB2 ...

The Natives are getting restless, an

overview of DB2 Stored Procedures

Frank Rhodes

BMC Software

September 16/17, 2015

Click to edit Master title style

Basis of Presentation

• Presentation based on research for managing schema

• This may be a different perspective than that of a DBA

who is considering using stored procedures in an

application

• This presentation is an overview of stored procedures

2


Topics

• History of Stored Procedures supported by DB2

• Anatomy of Stored Procedures

• The 3 types of Stored Procedures

• Advantages of one type over another

• Native SQL: Deployment and Schema Management

3


History of Stored Procedures in DB2

• Stored Procedures introduced in DB2v5

• Required manual insertion into catalog

• ‘Create procedure’ syntax introduced in DB2v6

• External SQL procedures introduced in DB2v7

• Native SQL procedures introduced in DB2v9

• Originally the DB2 ‘scripting’ language was C, COBOL,

etc.

4


LANGUAGE SQL

MODIFIES SQL DATA

DYNAMIC RESULT SETS 0

DISABLE DEBUG MODE

PACKAGE OWNER RDAMCG

ASUTIME NO LIMIT

COMMIT ON RETURN YES

(IN EMPLOYEE_NUMBER CHAR(8), IN RATE DECIMAL(6,2))

CREATE PROCEDURE MG017.SPSQN006

Anatomy of a Procedure

5

id

parms

options

(SYSPARMS)

(SYSROUTINES)


LANGUAGE SQL

MODIFIES SQL DATA

DYNAMIC RESULT SETS 0

DISABLE DEBUG MODE

PACKAGE OWNER RDAMCG

ASUTIME NO LIMIT

COMMIT ON RETURN YES

CREATE PROCEDURE MG017.SPSQN006CREATE PROCEDURE MG017.SPSQN006 id


parms(SYSPARMS)


Anatomy of a Procedure part 2

6

procedure body

comment

UPDATE MG017.TG01SS

SET SALARY = SALARY * RATE

WHERE EMPNO = EMPLOYEE_NUMBER;

UPDATE MG017.TG01SS



COMMENT ON PROCEDURE MG017.SPSQN006 IS

‘THIS IS A COMMENT’;

COMMENT ON PROCEDURE MG017.SPSQN006 IS

‘THIS IS A COMMENT’;

GRANT EXECUTE ON PROCEDURE MG017.SPSQN006

TO JOHNNY;

GRANT EXECUTE ON PROCEDURE MG017.SPSQN006

TO JOHNNY; grant

UPDATE MG017.TG01SS



COMMENT ON PROCEDURE MG017.SPSQN006

IS ‘THIS IS A COMMENT’;

procedure body

comment

(SYSROUTINEAUTH)


Three types of Stored Procedures

• External

• External SQL

• Native SQL

7


External Procedure – example

CREATE PROCEDURE ACMQA01.SPOP0001

( IN CODE CHAR (3)

,INOUT DESCRIP CHAR(10))

LANGUAGE C

EXTERNAL NAME SPOP1

PARAMETER STYLE DB2SQL

ASUTIME NO LIMIT

PROGRAM TYPE MAIN

COMMIT ON RETURN NO;

8

LANGUAGE C

EXTERNAL NAME SPOP1

Language

Load Module Name

No procedure body

LANGUAGE C Language

EXTERNAL NAME SPOP1 Load Module Name


Storing of procedures

• External Procedure

9

SYSROUTINES

SYSPARMS

SYSROUTINEAUTH


External Procedure continued

Languages supported by DB2

• Assembler

• C

• COBOL

• PL/I

• REXX

• JAVA

• Used to support COMPJAVA (compiled JAVA) but no more

10


How to Create an External Procedure

• Create a source module in a supported language

• Pre-compile, Compile and Link the source, creating a

Load Module and DBRM member

• Bind the DBRM member into a package (if contains SQL)

• Execute ‘Create Procedure’ DDL

11


Native SQL Procedures – advantages

• Use same SPL as External SQL procedures but MUCH

easier to build

• No DSNTPSMP – hooray!

• No WLM environment – hooray!

• Not converted to C program; SPL text is executed

interpretively

• Procedure body is stored in 2 mg CLOB column in

SYSROUTINES

21


Native SQL Procedures – advantages

• Besides ease of use there are cost savings and

performance advantages

• Native procedures may use the ZIIP engine when invoked from a

off mainframe client

• Native procedures run in DBM1 – especially good for data access

• But not so good for procedural processes

22


Native SQL Procedure - example

CREATE PROCEDURE MG017R.SPSQN047

(IN EMPLOYEE_NUMBER CHAR (8) FOR SBCS DATA

,OUT RATE DECIMAL (6,2)

)

VERSION V1

…

BEGIN

SELECT SALARY INTO RATE

FROM MG017R.TG01SS


END

23

procedure body


Storing of procedures

• External Procedure

• External SQL

• Native SQL

24

SYSROUTINES

SYSPARMS

SYSROUTINEAUTH

SYSROUTINE_SRC

SYSROUTINE_OPTS

SYSPACKAGE

SYSENVIRONMENT


Native SQL Procedures – versions

• One procedure can have many versions. New versions

are created using the ALTER statement

25

Myproc

V1CREATE PROCEDURE Myproc …

ALTER PROCEDURE Myproc ADD

VERSION V2 …Myproc

V2

Myproc

V3ALTER PROCEDURE Myproc ADD

VERSION V3 …


Native SQL Procedures – Active Version

• Only one version is ACTIVE at one time.

26

Myproc

V1

Myproc

V2

Myproc

V3

call

Myproc

call

Myproc

call

Myproc

PGM 2

PGM 1

Trigger

Myproc

V1

Myproc

V2

ALTER PROCEDURE Myproc ACTIVATE VERSION V2


Native SQL Procedures – How Versions Might Be Used

• Fallback if errors occur when procedure is in production

27

Myproc

V1

Myproc

V1

Myproc

V2

Myproc

V2

Myproc

V3

call

Myproc

call

Myproc

call

Myproc

PGM 2

PGM 1

Trigger

ALTER PROCEDURE Myproc ACTIVATE VERSION V1


Native SQL Procedures – Testing an inactive version

28

Myproc

V1

Myproc

V1

Myproc

V2

Myproc

V2

call

Myproc

call

Myproc

call

Myproc

PGM 2

PGM 1

Trigger

strcpy(strName,”Myproc”);

EXEC SQL SET PATH Myschema;

EXEC SQL SET CURRENT ROUTINE VERSION = V3;

EXEC SQL CALL :strName (‘AAAAA’);

call

Myproc

strcpy(strName,”Myproc”);

EXEC SQL SET PATH Myschema;

EXEC SQL SET CURRENT ROUTINE VERSION = V3;

EXEC SQL CALL :strName (‘AAAAA’);

Myproc

V3Testprog


Native SQL Procedures – Alter Statements

• Most of the options can be changed using an ALTER

statementALTER PROCEDURE A.B VERSION V2

NOT DETERMINISTIC

READS SQL DATA CREATE

• When updating the text and some options, an ALTER

REPLACE is requiredALTER PROCEDURE A.B

REPLACE VERSION V2

( IN A SMALLINT)

LANGUAGE SQL

...

New text

29


Native SQL Procedures – Maintenance Considerations

31

Myproc.V1ASULIMIT 1000CREATE PROCEDURE Myproc

ASULIMIT 1000 …

ALTER PROCEDURE Myproc ADD

VERSION V2 …

Myproc.V2NO ASULIMIT

• When you add a version (or alter replace a version), the

owner is always the owner of the original version

• When you add a version (or alter replace a version), the

owner is always the owner of the original version

• When executing an Add Version or Alter Replace, the

parms must be repeated in entirety.

• Challenges with Signature changes


Native SQL Procedures – Signature

• What is a Signature? The following:

• Schema name

• Procedure name

• Parms and their attributes (excluding name of parm)

• Option, PARAMETER CCSID

• All versions of a native procedure have to have the same

signature

• If you need to change part of the signature, you must

change it in all versions. You must drop all versions

(using drop procedure), then recreate all supported

versions.

32


Native SQL Procedures – PARAMETER CCSID

• Historically, you could always put the CCSID on the

parms if you didn’t want to use the default CCSID

• Later, DB2 introduced PARAMETER CCSID which

offered a convenient way of specifying the CCSID for all

character based parameters. You no longer had to repeat

the CCSID on each parm

• Of course, if CCSID is also specified on some of the

character based parms, the CCSID on the parms must

match the CCSID in PARAMETER CCSID.

33


Native SQL Procedures – DROP Options

34

Myproc

V1ALTER PROCEDURE Myproc DROP

VERSION V2;

Myproc

V2

Myproc

V3DROP PROCEDURE Myproc;


Native SQL Procedures – Rebinds

35

Myproc

V1

ALTER PROCEDURE Myproc REPLACE

VERSION V1 …;

Myproc

V2

Myproc

V3

Automatic rebind of Native Procedure

call

Myproc

call

Myproc

call

Myproc

PGM 2

PGM 1

TriggerREBIND TRIGGER … ;

REBIND MEMBER(PGM1) …;

REBIND MEMBER(PGM2) …;


Native SQL Procedures – Rebinds

36

Myproc

V1

An ALTER is performed against Table Mytab.

All packages accessing Mytab become

invalidated

Myproc

V2

Myproc

V3

Table

MytabNeed to find all packages

that reference Table Mytab.

Native Procedure package will have a type

of ‘N’ vs. the type of ‘P’ most packages have.

REBIND PACKAGE(Myschema.Myproc(V1))




• BIND PACKAGE(remote_location.collection_id)

COPY(sp_schema.sp_name) COPYVER(sp_ver)

ACTION(ADD)

• Process will define the package at a remote location but

not the procedure itself.

• Used when procedure is defined on ssid A but accesses

ssid B. Needs a package defined on ssid B to work.

38

Native SQL Procedures – Bind Copy AddRemote

Local

Remote


• BIND PACKAGE (remote_location.new_schema)

DEPLOY (sp_schema.sp_name)

COPYVER(sp_version)

ACTION (ADD) QUALIFIER(new_qualifier)

• The command will take a local procedure and define it on

remote DDF location.

• Viable way to move procedures to production

39

Native SQL Procedures – Bind DeployRemote

Local

Remote


• Bind Deploy discussed previously

• Data Studio

• Not a true Change Management tool

• Combination of vendor tools

• Source Management Tools

• Schema Management Tools

40

How to Move to Production


Native SQL Procedures – Format

41


Native SQL Procedures – Format

• The various formats which can be used determine the amount of

formatting which will be retained in the SPL text.

• --#SET SQLFORMAT SQL

• collapses each line of an SQL statement into a single line and discards

comments

• Not good for procedures

• --#SET SQLFORMAT SQLCOMNT

• Same as SQL except comments are retained

• --#SET SQLFORMAT SQLPL

• Retains comments and terminates each line of an SQL statement with a

line feed character (hex25)

• Good for procedures

42


BEGIN

DECLARE STMT CHAR(100);

DECLARE TABLE_NAME CHAR(30);

--FIRST COMMENT

SET STMT = 'DROP TABLE '||TABLE_NAME; --SECOND COMMENT

PREPARE S1 FROM STMT;

EXECUTE S1;

END

43

Native SQL Procedures – Format Examples Build with SQL

What gets saved in SYSIBM.SYSROUTINES(TEXT)

BEGIN DECLARE

STMT CHAR(100); DECLARE TABLE_NAME

CHAR(30); SET STMT = 'DROP TABLE

'||TABLE_NAME; PREPARE S1 FROM STMT;

EXECUTE S1; END

Note linefeed and comments are not maintained in the save text


BEGIN



--FIRST COMMENT



EXECUTE S1;

END

44

Native SQL Procedures – Format Examples Build with SQLCOMNT


BEGIN DECLARE

STMT CHAR(100); DECLARE TABLE_NAME

CHAR(30); --FIRST COMMENT

/n SET STMT = 'DROP TABLE '||TABLE_NAME; --SECOND COMMENT/n

PREPARE S1 FROM STMT; EXECUTE S1;

END

Note: Comments are saved with linefeeds, but no other linefeeds are

saved


BEGIN



--FIRST COMMENT



EXECUTE S1;

END

45

Native SQL Procedures – Format Examples Build with SQLPL


BEGIN\n DECLARE STMT CHAR(100);\n DECLARE TABLE_NAME CHAR(30);\n

--FIRST COMMENT\n SET STMT = 'DROP TABLE '||TABLE_NAME; --SECOND

COMMENT\n PREPARE S1 FROM STMT;\n EXECUTE S1;\nEND\n

Note the linefeeds and comments are both maintained in

the save text

Frank RhodesBMC Software

[email protected]

The Natives are getting Restless, an overview of DB2 Store Procedures


More Trivia

• Grants are at procedure level for Native procs

• Comments are at version level for Native procs

• Parm Names for External procs may be blank

• XML is not a valid datatype in DB2v9. But it is valid for

native procs in DB2v10

• Rowid is not a valid datatype for native procedures in any

version of DB2

• Datatype is carried as REAL/DOUBLE for parms instead

of FLOAT as in columns

47


More Trivia – II

• TIMEZONE syntax is spelled out for parms unlike the

behavior for columns.

• For external procs, if proc name is 8 bytes or less then

you do not have to specify an external name. The

external name will default to the name of the proc. The

keyword EXTERNAL needs to be included in the options.

48


More Trivia – III

• DB2 has option syntax for the following but does not store

values in catalog

• Scale portion of DECIMAL

• FOR UPDATE CLAUSE

• Following should be stored in SYSENVIRONMENT but

we never saw it happen

• TIME FORMAT (ISO/EUR/USA/JIS)

• DATE FORMAT (ISO/EUR/USA/JIS)

49


Native SQL Procedures – Maintenance Considerations

• When you alter certain options, you have to be ‘in the

same environment’ as the environment which existed for

the creation of the procedure. If not, a -4706 will be

issued. The options are

• QUALIFIER

• PACKAGE OWNER

• WLM ENVIRONMENT FOR DEBUG MODE

• OPTHINT

• SQL PATH

• DECIMAL if the value includes a comma

• Use Alter Replace to get around this restriction

50

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