How Adaptive Server IQ makes connections

3Locate a server. Using the connection parameters, the ODBC driver or Embedded SQL interface library must locate a database server on your machine or over a network.

4Locate the database. Once it locates the server, the ODBC driver or Embedded SQL interface library must locate the database you are connecting to.

The following sections describe each of these steps in detail.

Locating the interface library

ODBC driver location

Embedded SQL interface library location

The client application makes a call to one of the Adaptive Server IQ interface libraries. In general, the location of this DLL or shared library is transparent to the user. Here we describe how the library is located, in case of problems.

For ODBC, the interface library is also called an ODBC driver. An ODBC client application calls the ODBC driver manager, and the driver manager locates Adaptive Server IQ’s driver.

The ODBC driver manager looks in the supplied data source in the odbc.ini file or registry to locate the driver. When you create a data source using the ODBC Administrator, Adaptive Server IQ fills in the current location for your ODBC driver.

Embedded SQL applications call the interface library by name. The name of the Adaptive Server IQ Embedded SQL interface library is as follows:

Windows NT: dblib6t.dll

UNIX: dblib6 with an operating system-specific extension.

When the library is located

The locations that are searched depend on the operating system:

On Windows NT, the client application looks for files in the current directory, in the system path, and in the Windows and Windows\system directories.

On UNIX, the client application looks for files in the system path and the user path.

Once it locates the interface library, the client application passes a connection string to it. The interface library uses the connection string to assemble a list of connection parameters, which it uses to establish a connection to a server.

78

Page 98
Image 98
Sybase 12.4.2 manual Locating the interface library, How Adaptive Server IQ makes connections