4.8.New Features
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.Net Data Providers. A suite of Managed .Net Data Providers built with a thin generic .Net client classes for communicating with any of our supported Database agents on the Database Server, as well as a 100% Managed TDS based .Net Provider for connectivity to Microsoft and Sybase SQLServer Database eliminating the need for any software installation on the Database Server machine. An Umanaged .Net ODBC Provider is also available, which makes use of the OpenLink built in Cursor Library to provide a greater level of .Net support when connecting via an ODBC Datasource.
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Unicode Driver support. Database agents support the latest releases of all supported database engines this includes:
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Oracle 8i & 9i
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Microsoft SQL Server 2000
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DB/2 v7
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ODBC Agent
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JDBC Agent
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Informix 9
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Sybase Adaptive Server 12.5
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Progress 9 (SQL-92)
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Significant SQL Server and SYBASE Driver Enhancements. Our Drivers are now built to communicate directly with Microsoft SQL Server and SYBASE ASE using the TDS protocol (the native wire protocol for both database servers). This also implies that no additional software is required post installation in order for our ODBC Drivers to communicate with these Drivers (this applies to the Single Tier format Drivers only). The use of TDS has also enabled us to double the performance of both our Single Tier and Multi-Tier Drivers for these databases.
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Array Optimisations on Select Queries. All drivers now support the SQLSetStmtAttr(SQL_ARRAY_SIZE) call for batch select statements, providing improved performance when re-execute select statements with bound paramters.
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Deferred Fetching. The Release 4 OpenLink driver family brings marked communications layer improvements. Central to these are improved implementation of the
SQLGetData
andSQLPutData
ODBC function calls.Wholesale vs. Piecemeal Data Transfer. In previous releases of the drivers, parameter data at query execution was assembled in the OpenLink driver's client component and transferred to its server component in a single network hop. (The client and server components apply to both the Single- and Multi-Tier drivers; they refer to different layers within the driver entity.) Similarly, when fetching from a "long", or large binary data column, data was transferred from the driver's server component to the client component in a single network transfer. The only way data could manipulated in a piecemeal fashion, was within the ODBC application from the driver's client component (client side only).
The Release 4 driver family now allow transferring parameter data in parts over the network between the client and server driver components. Once transferred, the fragmented column data are re-pieced together in their entirety within the client and server portions of the driver.
Deferred Fetching. When fetching, data from columns with "long" data are only transferred between the server and client components if one of the following applies to that column:
It has been "bound" by the application via the SQLBindCol API call It has been retrieved via the SQLGetData API call This mechanism is referred to as deferred fetching. In this method, as "long" column data is not reassembled within the OpenLink ODBC client itself (rather, within the application), driver memory overhead incurred is dramatically reduced. Deferred fetching applies to the following "long" database column types:
- ODBC agent
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SQL_LONGVARCHAR
SQL_LONGVARBINARY
- DB/2 agent
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SQL_BLOB
SQL_CLOB
SQL_DBCLOB
If the long data compatibility option has been specified in the DB2 database
SQL_LONGVARCHAR
SQL_LONGVARBINARY
SQL_LONGVARGRAPHIC
- Oracle agent
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SQLT_BLOB
SQLT_CLOB
- Sybase agent
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CS_IMAGE_TYPE
CS_TEXT_TYPE
However, if a table contains a column defined as one of these "long" types, but the actual data stored in the column only fills a small proportion of the available space, deferred fetching is of no benefit. In these cases, performance may be improved by switching off the deferred fetching mechanism using the control in the OpenLink Generic Client data source setup dialog.