Jason Olson - IBM i DB2 Modernization to SQL

IBM i/DB2 Modernization to SQL

CM First Group. Confidential & Do Not Distribute 2
About Your Presenter
IBM i Professional for 16 Years.
Primary Focus is IBM i Engineering / Programming
Well Versed in 2E.
Well Versed in RPG (All Flavors)
Well Versed in CM Products such as Implementer
Up to Date on Newest SQL/RPG Enhancements.

Agenda
What Exactly is SQL (Just in case you don’t know. )
Benefits of Moving to SQL Created Objects
SQL Performance Benefits
SQL Objects vs DDS Objects
SQL Source vs DDS Source
Changing a 2E Model to Support SQL
SQL Specific Data Types

What Exactly is SQL?
SQL Stands for Structured Query Language.
Developed at IBM in the Early 1970s.
Consists of a DDL (Data Definition Language)
IE, CREATE TABLE, CREATE INDEX
Consists of a DML (Data Manipulation Language)
IE, INSERT INTO, UPDATE, DELETE,
To a Large Extent Consists of Simple English
Statements.

Whole World Uses SQL. New resources are more familiar with
SQL then DDS.
Long Field Names are Available to Outside World. YAY! 
Performance (Further discussion later)
Data is Validated when Written to the Database.
DDL Defined Indexes use a 64K page size vs 8K used by Logical
Files.
Null Capable Fields.
New Data Types (Blob, Clob, Lob) Demo of this!

No Enhancements to DDS Language.
Constraints are Built into Database.
Built in Encryption.
Easier Modification of Table Layouts.
RPG Programs that Use SQL Access Don’t Need a Re-
compile.
Automatic Identity Columns.

SQL Performance
In DDS Data is Validated When Read. In SQL Data is
Validated When Written.
This is Important as we Normally do many more reads
vs. writes. Ratio could be as high as 25 to 1.
Data Can Arrive up to 11 Seconds Faster. Especially
Helpful When Loading up Subfiles from Random Keys.
Concurrent Write Support.
Logical Page Size of 64K.

SQL Objects vs DDS Objects
DDS Objects Create Physical Files & Logical Files
The Object types are *FILE PF and *FILE LF
Most common source is DDS and stored in QDDSSRC.
Source Member type is PF for Physical files, and LF for Logical Files.
Compiled like a program using option 14 from PDM, or using the CRTPF or
CRTLF commands.
SQL Objects create Physical Files & Logical Files as well.
The Object types are *FILE PF and *FILE LF
Most common source is SQL and stored in QSQLSRC.
Source Member type can be named anything.

SQL Objects vs DDS Objects DSPFD

DDS Source is stored in source physical file QDDSSRC (Most Common)
Source is then compiled using CRTPF or CRTLF commands. (Option 14 in PDM)

SQL Source is stored in source file QSQLSRC (Most
Common)
Source member type can be named anything.
However, common examples are
SQLT for tables, SQLV for views and SQLI for indexes.
SQL Objects are created using the RUNSQLSTM
command.

Example SQL Table Source.

Example SQL View Source.

Example SQL Index Source.

Items to Note!
SQL objects are created using the RUNSQLSTM Command.
SQL View And Indexes produce separate IBM i Objects. (LFs)
No problem combining SQL Created tables and DDS Created LFs. (Common)

DML (Data Manipulation Language)
DML is used to manipulate the database.
Examples are,
SELECT ( to read data )
INSERT ( to insert data )
UPDATE (to update data)
DELETE (to delete data)
Big advantage is the use of the DB2 Database Engine for automatic index selection!
If an index exists that matches the search criteria then that index will be used
automatically. In standard record level access from RPG this is not the case.
SQL DML Statements can be incorporated directly into an RPG program! There is no
longer a need to use the traditional record level access provided by RPG.

Select (Statement Example)

INSERT (Statement Example)

UPDATE (Statement Example)
Can update multiple records at once!

DELETE (Statement Example)
Can delete multiple records at once!

Change Model to use SQL Support.
Several different approaches can be taken to change a model to support SQL.
You can change the model to use the 2E generated table name, but use longer
field name support. This allows you to expose the longer field names to the
outside world. No change to RPG.
You can change the model to use both the longer table name, and also the
longer field names. Again, easier for the outside world. No change to RPG.
You can change the generated function to use SQL record level access
regardless of the database type.

Any change to support SQL is done though the changing of model values.
Name Description Values
YSQLVNM SQL naming *DDS
YDDLDBA Database Access Method *RLA / *SQL
YSQLLEN SQL naming length 10 to 25
YSQLOPT Generate SQL OPTIMIZE clause *NO
YSQLFMT Generate SQL RCDFMT clause *NO
YSQLSTM SQL statement generation type *EXC
YSQLCOL Generate SQL Col/Library Name *YES
YLVLCHK Generate IDX with LVLCHK(*YES) *NO
YDBFGEN Method for database file generation DDS / SQL / DDL
YSQLWHR specifies whether to use OR or NOT logic when generating SQL WHERE clauses. The default is
*OR.
YSQLLCK

YSQLVNM relates to the naming scheme used for fields and files.
Values
*DDS – Uses the DDS name
*SQL – Use the names of the objects in the model.
*LNG – Use long names for fields and files
*LNF – Use long field names
*LNT – Use long table names

YDDLDBA
specifies a method of accessing the database
Values
*RLA
External function generates with RLA access.
*SQL
External function generates with SQL access.

YSQLLEN – The length of field names up to 25 characters.
Values
Any number between 10 and 25.

YSQLFMT
Specifies whether the RCDFMT keyword must be generated for SQL tables,
views, and indexes.
Values
*YES
the RCDFMT value is calculated using the same rules as are used when
DDS files are generated.
*NO
the record format is the same as the table, index, or view name.

YDBFGEN – Specifies the language used in creating the logical/view over a physical
file/table.
*DDS
*SQL
*DDL

Change existing table to SQL.
Generating SQL files
Extended Names?
Generating SQL Functions?
Generating RLA Functions over SQL Files

Change existing table to SQL.
There are options to consider when modernizing a file
name to SQL in 2E.
Keep the file and field names the same.
Keep the file name the same, give the fields enhanced
names.
Change the file and fields to enhanced names.

SQL Record access in Functions
Functions can be changed through model values, or one at a
time to SQL access by the use of function options.

SQL Specific Data Types
Use BLOB data type of store binary data.
SQL Only Data Type! (No DDS Support)
BLOBs can be up to 2GB in size! YAY!
Created As Column In Table Definition.
Can Store ANY Binary Data (Files, Audio, Emails, .EXE
Files)
Cannot Be Modified Outside of Program. (NOT in IFS)
Takes Advantage of IBM i Security.
Automatic Replication to Target HA System.

Wrap Up
Questions? Comments?

Jason Olson - IBM i DB2 Modernization to SQL

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