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v5:database:ibm_db2

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IBM DB2

Specification
Driver Namedb2
Data Providerdb2
StatusActive1)
WindowsYes
UnixYes
ADOdb V5Yes
ADOdb V6Yes
Alternative Drivers

ODBC Driver For IBM DB2

Description

This driver provides a connection to IBM DB2 Databases, using the IBM Data Client.

uCaseTables

syntax
 $db->uCaseTables = true/false;

Column names are now always returned in upper-case by the driver. Use of this variable is deprecated as of ADODb version 5.21.0 and will be removed in version 6.0.0

This variable sets the keys in MetaColumns,MetaPrimaryKeys and MetaForeignKeys to upper-case when retrieved. The default is true.

$mt = $db->getMetaColumns('ACT');
print_r($mt);
 
$db->uCaseTables = false;
$mt = $db->getMetaColumns('ACT');
print_r($mt);


Connection Example Using Instance

The DB2 database must be catalogued for a connection like this to work.

include '../adodb/adodb.inc.php';
$database = 'SAMPLE';
$user = 'db2inst1';
$password = 'instance';
$conn = ADOnewConnection('db2');
$conn->connect($database, $user, $password);

Connection Example Using DSN

include '../adodb/adodb.inc.php';
$dsn = 'hostname=192.168.0.30;protocol=tcpip;port=50000;database=SAMPLE;uid=db2inst1;pwd=instance';
$conn = ADOnewConnection('db2');
$conn->connect($dsn);

db2oci

Specification
Driver Namedb2oci
Data Providerdb2
StatusActive2)
WindowsYes
UnixYes
ADOdb V5Yes
ADOdb V6Yes

This driver re-maps ibm :0 bind variables to oracle compatible ? variables. Use this driver to enhance compatiblity between Oracle and DB2 drivers


db2ora

Specification
Driver Namedb2
Data Providerdb2
StatusObsolete3)
WindowsYes
UnixYes
ADOdb V5Yes
ADOdb V6No

This driver provides undocumented bind variable mapping from ibm to oracle.The functionality appears to overlap the db2_oci driver

Case Sensitivity In Table And Column Names

Unlike most DBMS, DB2 provides complete control over the casing of table and column names. This means, for example, that the tables ACCOUNTS, accounts and Accounts can exist simultaneously in the same database.

In normal usage, table and column names can be searched in a case insensitive manner. That insensitivity always applies precedence to the upper case table name. In this example, 2 tables exist: ACCOUNTS and accounts.

$sql = 'SELECT * FROM ACCOUNTS';
 
$sql = 'SELECT * FROM accounts';
 
/*
* Both of these queries will query the ACCOUNTS table
*/

In order to query the accounts table, it will be necessary to modify the SQL statement, using double quotes

$sql = 'SELECT * FROM "accounts"'

Query Precedence

The following order of query precedence applies:

  1. If a single table name exists in a database, the table can be queried in any way as long as the table name is not quoted
  2. If a single table name exists in a database, a query must match the casing of the name if the query table name is quoted
  3. If multiple tables with the same name apply, any unquoted query will search a table name with upper casing, no matter how the query table name is constructed.

Table Names With Special Characters

Any table name containing special characters will need to be quoted in all queries.

Using metaCasing with DB2

When using DB2, it is important to remember that when using metaCasing and having mixed or lowercase table names in the database may mean that tables may become difficult to access if the are not in the same casing convention as to what is normally used.

Generally, development standards mean that table names in a database are created to a casing standard, for example, all upper-case or lower-case table and column names. In that case, metaCasing will work the same as in other databases, e.g.

/*
* Connection to DB2 smple database, accessing a table called ACT
* Set the casing to lower case
*/
$db->setMetaCaseOption($db:METACASE_LOWER);
$cols = $db->metaColumnNames('ACT');
print_r($cols);
/*
 * Prints
Array(
  [0] => actno,
  [1] => actname,
  [2] => actdesc
  )
  */

These rules also apply to column naming

The Impact Of METACASE_NATIVE

Setting the metaCasing option to METACASE_NATIVE has an impact on the entire life cycle of a table, and it's use should be understood.

Creating Tables

Consider the following case-sensitive table name: accountTable, and how it is created and referenced in ADOdb.

MetaCaseCreated AsSQL RetrievalPresentation in MetaFunctions
METACASE_UPPERACCOUNTTABLESELECT FROM ACCOUNTTABLE,accountttable,accountTable etc.ACCOUNTTABLE
METACASE_LOWERACCOUNTTABLESELECT FROM ACCOUNTTABLE,accountttable,accountTable etc.accounttable
METACASE_NATIVEaccountTableSELECT FROM “accountTable”accountTable

As shown, once a table is created in non-upper case when the metaCasing value is METACASE_NATIVE, it must always be retrieved using the same casing, and all SQL operations must quote the table names. The functions autoExecute(),getInsertSql(), and getUpdateSql() will automatically quote table and column names if METACASE_NATIVE is set. For DB2, this behaviour overrides the $quoteFieldnames parameter.

1) , 2)
This driver is actively supported by ADOdb project members
3)
This driver is not supported, and will be removed in ADOdb V6
v5/database/ibm_db2.1449170994.txt.gz · Last modified: 2017/04/21 11:25 (external edit)