5. ODBC Drivers

5.2. Unix Data Source Configuration

The OpenLink ODBC Lite for UNIX is the family name of a suite of Single Tier ODBC Drivers supporting a wide range of leading relational database engines. These drivers do not require the installation of any additional software on the server machine hosting the database engine. This is due to the fact that Single Tier driver implementations depend on the database(s) that you are connecting with to provide database connectivity and network services (this software typically installed at database engine installation time).

Before a Lite Driver can be used, a data source must be defined either manually, or by using the HTTP based iODBC Administrator.

5.2.1. Creating Data Sources Using iODBC Administrator

The OpenLink Lite Drivers for Unix can be installed within a previously installed Multi-Tier installation or completely standalone. If installed within a Multi-Tier installation the Lite Driver can share the Admin Assistant installed with the Multi-Tier for configuring data source. In the absence of a Multi-tier installation, an HTTP based iODBC Administrator is installed and used to configure the drivers. The download wizard for Unix Lite will always offer install.sh and the HTTP based iODBC Administrator, and then show the available Lite Drivers for the required operating system.

A Lite driver package contains only the driver and installation files, e.g. the sql_lt.taz file contains:

      bin/openlink.ini		Contains the Environment settings
      bin/inifile
      bin/freetds.conf		Part of the FreeTDS library
      lib/sql_st_lt.la
      lib/sql_st_lt.so		The actual lite driver
      scripts/SQLServer/oplrvc.sql
    

During the installation of the OpenLink Lite Drivers for Unix, the install.sh script will generate a file called bin/iodbc-admin-httpd.sh. This is a shell script used to start and stop the HTTP based iODBC Administrator. The usage is as follows:

      $ iodbc-admin-httpd.sh start  # Starts the HTTP based iODBC Administrator
      $ iodbc-admin-httpd.sh stop   # Tries to stop the HTTP based iODBC Administrator
      $ iodbc-admin-httpd.sh status # Shows if the program is running
    

5.2.1.1. Wizard Based Configuration

5.2.1.2. Form Based Configuration

The OpenLink HTTP based iODBC Administrator also allows the more experienced OpenLink ODBC user to manage ODBC DSNs via a forms based interface. Like the wizard based approach, this is done entirely from within your browser. In the sections that follow, a step by guide and illustrative screen shots are used to demonstrate the process of creating the same Lite ODBC DSN created in the prior section using the Wizard approach.

5.2.2. Manual Configuration

5.2.3. DB2

OpenLink Lite Drivers for Unix can be configured in 3 ways:

5.2.4. Informix

OpenLink Lite Drivers for Unix can be configured in 3 ways:

5.2.5. Ingres

OpenLink Lite Drivers for Unix can be configured in 3 ways:

5.2.6. Oracle

OpenLink Lite Drivers for Unix can be configured in 3 ways:

5.2.7. PostgreSQL

OpenLink Lite Drivers for Unix can be configured in 3 ways:

5.2.7.1. Datatype Mapping from ODBC Datatypes to Postgres Datatypes

This information can be queried by the SQLTypeInfo catalog call.

5.2.7.2. Datatype Mapping from Postgres Datatypes to ODBC Datatypes

This information can be queried by the SQLColumns catalog call.

(*) Note: An oid is returned as a SQL_INTEGER, because otherwise it would not be useable for SQLSpecialColumns.

Binary data / large objects are not supported in this release.

5.2.8. MySQL

OpenLink Lite Drivers for Unix can be configured in 3 ways:

5.2.8.1. Datatype Mapping from ODBC Datatypes to MySQL Datatypes

This information can be queried by the SQLTypeInfo catalog call.

5.2.8.2. Datatype Mapping from MySQL Datatypes to ODBC Datatypes

This information can be queried by the SQLColumns catalog call.

5.2.9. Progress SQL92

OpenLink Lite Drivers for Unix can be configured in 3 ways:

5.2.10. Microsoft or Sybase SQL Server (TDS)

5.2.10.1. Installation

Login to your Unix or Linux client machine.

Figure: 5.2.10.1.1.

cd into the installation directory.

Figure: 5.2.10.1.1.

The installation files ship as an installation shell script, a driver and admin .taz file, and a license .lic file. The installation shell script should be ftp'd in ascii. The rest of the files should be ftp'd in binary, where applicable.

Figure: 5.2.10.1.1.

Run the following command to start the installation: sh install.sh

Figure: 5.2.10.1.1.

If you have a pre-existing installation running on the machine, you will be presented with the following options.

Figure: 5.2.10.1.1.

You must choose a TCP port on which to run your HTTP-based iODBC Data Sources Administrator. The default is 8000. You will need to know this port number and your local machine's IP address or hostname to access your Admistrator in a Web browser. This is how you call it: http://machine:portnumber

Figure: 5.2.10.1.1.

This enables you to name your administrator's log file. It is best to go with the default.

Figure: 5.2.10.1.1.

You can choose to log all requests. This is not diagnostic-level odbc tracing or connection logging. The default is no.

Figure: 5.2.10.1.1.

You can change the iODBC Data Source Administrator's default username from "admin". This is the name that you will need to login to OpenLink's HTTP-based iODBC Data Sources Administrator.

Figure: 5.2.10.1.1.

You can change the iODBC Data Source Administrator's default password from "admin".

Figure: 5.2.10.1.1.

The installation is complete.

Figure: 5.2.10.1.1.

5.2.10.2. Configuration

Execute the bash command to open a bash shell. If you do not have have the bash shell, substitute the sh command for the bash command. This will open the bourne shell.

Figure: 5.2.10.2.1.

Use the export command to set an OPL_LICENSE_DIR variable that points to the directory that contains your OpenLink license. This is typically the bin sub-directory of the OpenLink installation. However, you can put your license files in /etc/, the root of the installation, or virtually anywhere else.

Figure: 5.2.10.2.1.

Run the following command to set your ODBC environment variables: . ./openlink.sh

Figure: 5.2.10.2.1.

cd into the bin sub-directory of your OpenLink installation.

Figure: 5.2.10.2.1.

Use the ls(1) command to display your files.

Figure: 5.2.10.2.1.

Run the following command to start your HTTP-based iODBC Data Sources Administrator: ./iodbc-admin-httpd.sh start

Figure: 5.2.10.2.1.

Open a Web browser on any computer and type the URL for your administrator in the address bar.

Figure: 5.2.10.2.1.

Click the Client Components Administration link in the left hand side navigation bar.

Figure: 5.2.10.2.1.

Click the Configure ODBC Data Sources link in the left hand side navigation bar.

Then, login with your username and password.

Figure: 5.2.10.2.1.

Click the Add button.

Figure: 5.2.10.2.1.

Click the OpenLink SQL Server Lite Driver (multi-threaded). Then, click Create DSN.

Figure: 5.2.10.2.1.

Provide a descriptive name and optional name for your DSN. Then, click Next.

Figure: 5.2.10.2.1.

Pass the following values in the next dialog:

Figure: 5.2.10.2.1.

• Database Name - A valid SQL Server database name
• Connection Options - The driver accepts the following Connection Options:
  • -H - Hostname of the machine on which SQL Server is running
  • -P - SQL Server TCP Port
  • -V - SQL Server version. Values supported are: 9.0 equals SQL Server 2005; 8.0 equals SQL Server 2000; 7.0 equals SQL Server 7
  • -S - SQL Server name on the specified host. A SQL Server instance can also be specified by appending "\InstanceName" to the ServerName ie "ServerName\InstanceName"
  • -F - Specify fail-over server name for Database Mirroring
  • -N - Network Packet size, a value that determines the number of bytes per network packet transferred from the database server to the client. The correct setting of this attribute can improve performance. When set to 0, the initial default, the driver uses the default packet size as specified in the Sybase server configuration. When set to -1, the driver computes the maximum allowable packet size on the first connect to the data source and saves the value in the system information.
  • -O Prepared Method, which is a value that determines whether stored procedures are created on the server for every call to SQLPrepare(). When set to Full (2), stored procedures are created for every call to SQLPrepare, which can decrease performance when processing static statements. When set to Partial(1), the initial default, the driver creates stored procedures only if the statement contains parameters. Otherwise, the statement is cached and executed directly at SQLExecute() time. When set to None (0), the driver never creates stored procedures.
  • -L - The name of a Microsoft SQL Server supported national language. The default language is English.
  • -C - The name of an installed character set on the server. By default it is the setting on the Microsoft SQL Server.
  • -A - Turn Off ANSI NULL handling
  • -E - Turn On SSL Strong Data Encryption
  • -R - Turn On SSL Server Certificate Verification
  • -D - Specify Name of Certificate Authority file to be used for SSL Certificate Verification
  • -Z - Turn On Snapshot Serializable Isolation
  • -M - Turn On Multiple Active Result Sets (MARS)
• Username - SQL Server login

Click Next.

Set the following variables on the next dialog:

Figure: 5.2.10.2.1.

• Existing Environment - This arbitrary heading for a collection of DBMS-related environment variables usually corresponds with the DBMS version
• New Environment - You can choose a new heading
• FREETDSCONF - The full path to the freetds file that installs with OpenLink's Single-Tier drivers
• DSQUERY - SQL Server instance name
• TDSHOST - SQL Server database server hostname or IP address
• TDSPORT - SQL Server listen port
• TDSVER - The SQL Server TDS version
• SQLSERVER_CATALOG -
• CURSOR_SENSITIVITY - Enables or disables the row version cache used with dynamic cursors. When dynamic cursor sensitivity is set high, the Cursor Library calculates checksums for each row in the current rowset and compares these with the checksums (if any) already stored in the row version cache for the same rows when fetched previously. If the checksums differ for a row, the row has been updated since it was last fetched and the row status flag is set to SQL_ROW_UPDATED. The row version cache is then updated with the latest checksums for the rowset. From the user's point of view, the only visible difference between the two sensitivity settings is that a row status flag can never be set to SQL_ROW_UPDATED when the cursor sensitivity is low. (The row status is instead displayed as SQL_ROW_SUCCESS.) In all other respects, performance aside, the two settings are the same. Deleted rows don't appear in the rowset. Updates to the row since the row was last fetched are reflected in the row data, and inserted rows appear in the rowset, if their keys fall within the span of the rowset. If your application does not need to detect the row status SQL_ROW_UPDATED, you should leave the 'High Cursor Sensitivity' checkbox unchecked, as performance is improved. The calculation and comparison of checksums for each row fetched carries an overhead. If this option is enabled, the table oplrvc must have been created beforehand using the appropriate script for the target database.

Click Next.

You can set the following, optional values on the fourth dialog:

Figure: 5.2.10.2.1.

• Read-only connection - Specifies whether the connection is "Read-only." Make sure the checkbox is unchecked to request a "Read/Write" connection.
• Defer fetching of long data - Defers fetching of LONG (BINARY, BLOB etc.) data unless explicitly requested in a query. This provides significant performance increases when fields in query do not include LONG data fields.
• Disable interactive login - Suppresses the ODBC "Username" and "Password" login dialog boxes when interacting with your ODBC DSN from within an ODBC compliant application.
• Jet fix - Check this checkbox if you intend to use this driver with Microsoft Access.
• No AutoCommit - Changes the default commit behaviour of the OpenLink driver. The default mode is AutoCommit (box unchecked).
• No RowSetSize limit - Disables a limitation enforced by the cursor library. This limitation is enforced by default. It prevents the driver from claiming all available memory in the event that a resultset generated from an erroneous query is very large. The limit is normally never reached.

Click Next.

Additional, optional parameters appear on the fifth, and final dialog:

Figure: 5.2.10.2.1.

• Row buffer size - This attribute specifies the number of records to be transported over the network in a single network hop. Values can range from 1 to 99.
• Max Rows - Allows you to define a limit on the maximum number of rows to be returned from a query. The default value of 0 means no limit.
• SQL_DBMS_Name - Manually overrides the SQLGetInfo(SQL_DBMS_NAME) response returned by the driver. This is required for products like Microsoft InfoPath for which the return the value should be "SQL Server".
• Initial SQL - Lets you specify a file containing SQL statements that will be run automatically against the database upon connection.

Click Next.

Your new DSN is highlighted and persisted on the the Data Sources tab. Click the Test tab.

Figure: 5.2.10.2.1.

Type your password in the password field and click test.

Figure: 5.2.10.2.1.

You have established a connection.

Figure: 5.2.10.2.1.

5.2.11. ODBC-JDBC Bridges for Java

OpenLink Lite Drivers for Unix can be configured in 3 ways: