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Programming Interfaces
Data Management : Database Access : Database connections : Connection failures and disruptions
 
Connection failures and disruptions
Database connections might fail for a number of reasons, such as:
*The database server for multi-user database access is not available—perhaps the network is down, or the network has not been started, or the network parameters are incorrect.
*The logical name of the application database already exists for the current session.
*The syntax for a connection parameter is wrong.
*The connection exceeds the maximum number of users per database (–n).
The following table lists the default failure behavior for each of the run-time connection techniques.
Table 2. Connection failure behavior
Connection technique
Default connection failure behavior
At OpenEdge startup
The OpenEdge session does not run.
CONNECT statement
The procedure executes up to the CONNECT statement where the connection failure occurs. The connection failure raises the error condition for the procedure. OpenEdge error processing does not undo database connections or disconnections. Any database connected in the procedure before the failed database connection remains connected.
Auto-connect
The procedures that contain a reference to the auto-connect database do not run, and a stop or break condition results in the calling procedure.
OpenEdge displays any connection error messages at the point of failure.
Before running a procedure or subprocedure, OpenEdge checks the procedure for database references. For each reference, OpenEdge searches through all of the connected databases, trying to find the corresponding database. If the database is not found, OpenEdge again searches all of the connected databases for an auto-connect list with an entry for that database. If an entry is found, OpenEdge connects the database. If no entry is found, OpenEdge does not run the procedure and raises a stop or break condition in the calling procedure.
Server, network, or machine failures can disrupt an application, even after a successful connection. If a failure occurs while a subprocedure is accessing a database, OpenEdge raises a stop or break condition in the calling procedure.
The following sections present a number of recommendations to help you manage database connection failures and disruptions in an application.
* Using CONNECT with NO-ERROR
* Using the CONNECTED function