Home | Previous Page | Next Page   Configuring Data Sources > Configuring a DSN on UNIX >

The odbc.ini File

The odbc.ini file is a sample data-source configuration information file. For the location of odbc.ini file, see the release notes. To create this file, copy odbc.ini to your home directory as $HOME/.odbc.ini (note the added dot at the beginning of the filename). Every DSN to which your application connects must have an entry in this file. The following table describes the sections in $HOME/.odbc.ini.

Section Description Status
ODBC Data Sources This section lists the DSNs and associates them with the name of the driver. You need to provide this section only if you use an ODBC driver manager from a third-party vendor. Required
Data Source Specification Each DSN listed in the ODBC Data Sources section has a Data-Source Specification section that describes the DSN. Required
ODBC This section lists ODBC tracing options. Optional

ODBC Data Sources

Each entry in the ODBC Data Sources section lists a DSN and the driver name. The data_source_name value is any name that you choose. It is like an envelope that contains all relevant connection information about the DSN.

The following example illustrates an ODBC data-source format: 

[ODBC Data Sources] 
data_source_name=INFORMIX ODBC 3.81 Driver 

·
·
·

The following example defines two DSNs called EmpInfo and CustInfo: 

[ODBC Data Sources] 
EmpInfo=IINFORMIX ODBC 3.81 Driver 
CustInfo=INFORMIX-CLI 2.8 Driver

Data-Source Specification

Each DSN in the data-sources section has a data-source specification section.

The following example illustrates a data-source specification format: 

[data_source_name] 
Driver=driver_path 
Description=data_source_description 
Database=database_name 
LogonID=user_id 
pwd=user_password 
Server=database_server 
CLIENT_LOCALE=application_locale 
DB_LOCALE=database_locale 
TRANSLATIONDLL=translation_path 
CURSORBEHAVIOR=cursor_behavior
DefaultUDTFetchType=default_UDT_Fetch_type
ENABLESCROLLABLECURSORS=enable_scroll_cursors
ENABLEINSERTCURSORS=enable_insert_cursors
OPTIMIZEAUTOCOMMIT=optimize_auto_commit
NEEDODBCTYPESONLY=need_odbc_types_only
OPTOFC=open_fetch_close_optimization
REPORTKEYSETCURSORS=report_keyset_cursors
FETCHBUFFERSIZE=fetchbuffer_size
DESCRIBEDECIMALFLOATPOINT=describe_decimal_as_float
USESERVERDBLOCALE=use_server_dblocale
DONOTUSELVARCHAR=do_not_use_lvarchar
REPORTCHARCOLASWIDECHARCOL=char_col_as_widechar_col
[ODBC]
   UNICODE=unicode_type

The following table describes the keywords that are in the data-source specification section and the order that they appear in each section.

Keywords Description Status
data_source_name Data source specified in the Data Sources section Required
driver_path Path for the driver

Set this value to the complete pathname for the driver library. For more information on the library directory and filenames, see the release notes.

 Required
data_source_description Description of the DSN

Configured for a single user or for system users.

 Optional
database_name Database to which the DSN connects by default Required
user_id User identification or account name for access to the DSN Optional
user_password Password for access to the DSN Optional
database_server Informix database server on which database_name resides Required
application_locale (GLS only) Client locale.

Default value: en_us.8859-1

 Optional
database_locale (GLS only) Database locale. Default value: en_us.8859-1 Optional
translation_path (GLS only) DLL that performs code-set conversion; default value:
$INFORMIXDIR/lib/esql/ig04a304.xx, where xx represents a platform-specific file extension		 Optional
cursor_behavior_name Flag for cursor behavior when a commit or rollback transaction is called.

Possible values are:

  • 0=close cursor
  • 1=preserve cursor

Default value: 0

 Optional
default_UDT_Fetch_type Default UDT fetch type.

Default value: SQL_C_BINARYPossible values are:

  • SQL_C_BINARY
  • SQL_C_CHAR
 Optional
Enable_scroll_cursors If this option is activated, the IBM Informix ODBC Driver supports only scrollable, static cursors.

Available only as a connection option: 

SQL_INFX_ATTR_ENABLE_SCROLL_CRUSORS

or as a connection attribute string: 

EnableScrollableCursors
Default value is: 0 (disabled)		 Optional
Enable_insert_cursors Reduces the number of network messages sent to and from the server by buffering the inserted rows used with arrays or parameters and insert statements. This option improves the performance of bulk insert operations.

Available as both a connection and statement option: 

SQL_INFX_ATTR_ENABLE_INSERT_CURSORS

or as a connection attribute string: 

EnableInsertCursors

Default value is: 0

 Optional
optimize_auto_commit Defers automatic commit operations while cursors remain open. This option can reduce database communication when the application is using non-ANSI logging databases.

Available as a connection option: 

SQL_INFX_ATTR_OPTIMIZE_AUTOCOMMIT

or as a connection attribute string: 

OptimizeAutoCommit

Default value is: 1 (enabled)

 Optional
open_fetch_close_optimization Causes the driver to buffer the open, fetch, and close cursor messages to the server. This option eliminates on or more message cycles when you use SQLPrepare, SQLExecute, and SQLFetch statements to fetch data with a cursor.

Only available as a connection option: 

SQL_INFX_ATTR_OPTOFC

or as a connection attribute string: 

OPTOFC

Default is: 0 (disabled)

 Optional
Report_keyset_cursors Causes the driver to report (via SQLGetInfo) that is supports forward-only, static, and keyset-driver cursors even though the driver only supports forward-only and static cursors. This option is used to enable dynaset-type functions, such as MicroSoft Visual Basic, which require drivers that support keyset-driven cursors.

Also available as connection option: 

SQL_INFX_ATTR_REPORT_KEYSET_CURSORS

or as a connection attribute string: 

ReportKeysetCursors

Default is: 0 (disabled)

 Optional
fetchbuffer_size Size of a fetch buffer in bytes.

Available as connection attribute string: 

FETCHBUFFERSIZE

Default is: 4096

 Optional
describe_decimal_as_float Describes all floating-point decimal columns as:
  • Float(SQL_REAL) or
  • Float(SQL_DOUBLE)

A floating-point decimal column is a column that was created without a scale, for example DECIMAL(12). Some prepackaged applications such as Visual Basic can not properly format Decimal columns that do not have a fixed scale. To use these applications, you must enable this option or redefine the column with a fixed scale.

Enabling this option has the disadvantage that SQL_DECIMAL is an exact numeric data type while SQL_REAL and SQL_DOUBLE are approximate numeric data types. SQL_DECIMAL with a precision of 8 or less will be described as SQLREAL. With a precision greater than 8, it is described as SQL_DOUBLE.

Available as connection attribute string: 

DESCRIBEDECIMALFLOATPOINT

Default is: 0 (disabled)

 Optional
use_server_dblocale Users server database locale.

Available as a connection attribute string: 

USERSERVERDBLOCALE

Default is: 0 (disabled)

 Optional
do_not_use_lvarchar If enabled, the SQLGetTypeInfo does not report LVARCHAR as a supported type (DATA_TYPE) of SQL_VARCHAR. Some applications will use LVARCHAR instead of VARCHAR, even in columns that are less than 256 bytes. The minimum number of bytes transmitted for LVARCHAR is higher than VARCHAR. A large number of LVARCHAR columns can result in the rowset size exceeding the maximum.

Enable this option only if your SQL_VARCHAR columns are less than 256 bytes.

Available as a connection attribute string: 

DONOTUSELVARCHAR

Default is: 0 (disabled)

 Optional
char_col_as_widechar_col Causes SQLDescribeCol to report character columns as wide character columns as follows:
  • SQL_CHAR is reported as SQL_WCHAR
  • SQL_VARCHAR is reported as SQL_WVARCHAR
  • SQL_LONGVARCHAR is reported as SQL_WLONGVARCHAR

Available as a connection attribute string: 

REPORTCHARCOLASWIDECHARCOL

Default is: 0 (disabled)

 Optional
unicode_type Indicates the type of Unicode used by an application. This attribute is applies to UNIX applications only and is set in the ODBC section of the odbc.ini file. The following considerations apply:
  • Application on UNIX not linking to Data Direct ODBC driver manager should set this to UCS-4
  • Applications on IBM AIX with version lower than 5L should set this to UCS-2
  • Applications using Data Direct driver manager do not need to set this attribute.

Default is: UTF-8

For more information on using Unicode in an ODBC application, see Unicode.

 Required

The following example shows the configuration for a DSN called EmpInfo: 

[EmpInfo] 
Driver=/informix/lib/cli/iclis09b.so 
Description=Demo data source 
Database=odbc_demo 
LogonID=admin 
pwd=tiger 
Server=ifmx_91 
CLIENT_LOCALE=en_us.8859-1 
DB_LOCALE=en_us.8859-1 
TRANSLATIONDLL=/opt/informix/lib/esql/igo4a304.so

The following example shows the configuration for a DSN called Informix 9: 

[Informix9] 
Driver=/work/informix/lib/cli/iclis09b.so 
Description=Informix 9.x ODBC Driver 
LogonID=user1 
pwd=tigress4 
Database=odbc_demo 
ServerName=my_server

If you specify a null LogonID or pwd, the following error occurs: 

Insufficient connect information supplied

Tip:
You can establish a connection to a DSN with null values for LogonID and pwd if the local Informix database server is on the same computer where the client is located. In this case, the current user is considered a trusted user.

A sample data source, with no LogonID and pwd, where the server and client are on the same computer, might look like the following example: 

Driver=/work/informix/lib/cli/iclis09b.so 
Description=Informix 9.x ODBC Driver 
LogonID= 
pwd=tiger 
Database=odbc_demo 
ServerName=ifmx_server
Home | [ Top of Page | Previous Page | Next Page | Contents | Index ]