Sybase Adaptive Server IQ 12.4.2, Administration And Performance Manual

Page: 97 / 536

CHAPTER 2 Running Adaptive Server IQ
77
How Adaptive Server IQ makes connections
This section describes how the interface libraries establish connections.
Who needs to read
this section? In many cases, establishing a connection to a database is straightforward using
the information presented in the preceding sections of this chapter. However, if
you are having problems establishing connections to a server, you may need to
understand how Adaptive Server IQ establishes connections in order to resolve
your problems.
Note If you have no problem establishing connections to your database, you
do not need to read this section.
The software follows exactly the same procedure for each of the following
types of client application:
• Any ODBC application using the
SQLDriverConnect
function, which is the
common method of connection for ODBC applications. Many application
development systems, such as Sybase PowerBuilder and Power++, belong
to this class of application.
• Any client application using Embedded SQL and using the recommended
function for connecting to a database (
db_string_connect
).
The SQL CONNECT statement is available for Embedded SQL
applications and in Interactive SQL. It has two forms:
CONNECT AS...
and
CONNECT USING...
. All the database administration tools, including
utilities and Interactive SQL, use
db_string_connect
.
Steps in establishing a connection
To establish a connection to Adaptive Server IQ, the client application carries
out the following steps:
1 Locate the interface library. The client application must locate the ODBC
driver or Embedded SQL interface library.
2 Assemble a list of connection parameters. Connection parameters may be
provided in several places, such as data sources, a connection string
assembled by the application, and an environment variable. The ODBC
driver or Embedded SQL interface library assembles the parameters into a
single list.