The 

odbc_exec()

 function nearly corresponds to the 

mysql_query() 

function. 

The only difference is that the 

odbc_exec()

 function needs two parameters where 

the first parameter is the 

connection id

 returned by the 

odbc_connect

 statement:

resource odbc_exec ( resource connection_id, string query_string)

To get each row by row in an array equivalent to the 

mysql_fetch_row()

 function 

the 

odbc_fetch_into()

 function can be used without great modifications. There 

are only syntax differences in both statements in our case.

A problem can occur when converting SQL statements with variables to ODBC. 

In our MySQL example above, the 

$id

 variable is in single quote (

`

) whereas in 

the DB2 example the single quotes are removed. The background for the change 

is that the table column 

ID

 is of type integer, and ODBC does not convert strings 

to integer automatically whereas in the MySQL function it does.

Attention:

 When using ODBC functions, variable contents in a SQL 

statement are

 not

converted to the correspondent type of the database 

column. ODBC expects that the variable in the SQL statement has the correct 

data type defined.

INSERT, UPDATE,and DELETE statements

In fact for all three SQL commands, 

INSERT

, 

UPDATE

, and 

DELETE

 the same 

MySQL and ODBC functions are used as discussed for the 

SELECT

 statement:

mysql_query($sql_statement)

odbc_exec($db,$sql_statement)

In Example 7 26 and Example 7 27, the difference between the MySQL and 

ODBC functions for the INSERT statement is shown.

Example 7 26   MySQL insert statement

$ret=mysql_query("INSERT INTO warenkorb (user_id, ktg_id) VALUES 

( $user_id , $ktg_id )");

if ($ret){

$text="Item ".$artnr." was inserted in the shopping cart";

}else{

$text="Insert failure of item ".$artnr." into the shopping cart";

}

echo $text;

Example 7 27   DB2 insert statement

$ret=odbc_exec($db,"INSERT INTO warenkorb (user_id, ktg_id) VALUES 

( $user_id , $ktg_id )");

if ($ret){

 Chapter 7. Application porting 

181