database. The background for this approach is that compared to DB2, MySQL 

does not have schemas, nor instances. 

In MySQL, a table can be referenced by 

database.tablename

. If no database 

name is provide in the table name, the default is the currently used database. In 

DB2, table name is defined as 

schema.tablename.

 When reference to a DB2 

table, if no schema is provided, the default schema is the user ID which is 

connected to the database. In an application, the 

set schema

 statement can be 

used to provide a global schema name for the tables which do not have a full 

table name specified. To simplify the application conversion, during database 

porting the tables were created with the schema of the MySQL database name 

(in our case 

itsodb

). By using the 

set schema

 after database connection, we do 

not need to change every table name in the application.

Example 7 23   Connecting a DB2 database

$db_user   =       "itsosj";

$db_pass   =       "itsosj";

$datab     =       "itsodb";

$db=odbc_connect($datab,$db_user,$db_pass) or die("Could not connect ".

odbc_errormsg());

$query="SET CURRENT SCHEMA= ITSODB ";

odbc_exec($db,$query) or die(odbc_errormsg($db));

A complement function to the persistent connect function 

mysql_pconnect() 

is 

the

 odbc_pconnect(). 

SELECT query statements

Querying a table in MySQL using the PHP MySQL functions is shown in 

Example 7 24. 

Example 7 24   MySQL select example

$sql = mysql_query("SELECT * FROM catalog WHERE id= $id ");

 $rowsql = mysql_fetch_row($sql);

 $graphic = "../graphic/".$rowsql[11].".jpg";

The correspondent ODBC DB2 query is shown in Example 7 25.

Example 7 25   DB2 select example

$sql = odbc_exec($db,"SELECT * FROM catalog WHERE id=$id");

 odbc_fetch_into($sql,$rowsql);

 $graphic = "../graphics/".$rowsql[11].".jpg";

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MySQL to DB2 UDB Conversion Guide