MySQL

DB2 UDB 

show index from tablename

select indname from syscat.indexes where 

tabname=tablename

Referential integrity

Referential integrity is the constraints defined on the table and its columns, which 

helps you to control the relationship of data in different tables. Essentially, it 

involves primary keys, foriegn keys, and unique keys.

Primary keys and unique keys are treated similarly in MySQL and DB2 UDB 

whereas MySQL currently only parses foreign keys syntax in 

create table 

statement, but does not use/store the information about foriegn keys except in 

InnoDB tables which support checking of foreign key constraints, including 

CASCADE

, 

ON DELETE

, and 

ON UPDATE

.

DB2 UDB provide full support for foreign keys. With the full referential integrity 

functionality from DB2 UDB, your application can be released from the job of 

taking care of the data integrity issue. Example 5 12 shows creation and usage 

of foreign key constraint in DB2 UDB.

Example 5 12   Foriegn key constraint usage

db2> alter table itsotable1 add constraint foreign1 foreign key (id)

     references itsotable2 on delete set null

We discuss more about foriegn keys creation in Section 5.5,  Sample database 

migration  on page 117

5.4  Porting database

Now you have understand MySQL database structure/schema relative to 

different types of DB2 UDB objects, such as database, tables, views, indexes and 

referential integrity, in this section we give you details of the database 

structure/schema conversion from existing MySQL database to DB2 UDB. 

Database schema conversion can be done in various ways but most common 

approaches are:

Automatic conversion using porting tools

Manual porting

Metadata transport

In general all the above approaches take existing MySQL database as input and 

pass it through following functional engine:

 Chapter 5. Database porting 

111