Clients are connected to the LinkDB via PARTapplicationServer by default.
In a client-server environment, you will find the AppServer client item on the server.
By default, the option Catalogs, search and database via AppServer [Catalog browsing, search and database with AppServer] is set on the Settings tab page under Connection to AppServer [AppServer connection].
The AppServer client item is missing on Clients.
LinkDB SQL calls are routed to the Appserver. The query is sent to the AppServer and then from the AppServer returned to DB. The way back to the Client is optimized because data are zipped. With JDBC this was not the case. That's why the connection is faster now.
Scripts made by consulting can still stay on the clients.
For database connections sessions are established. These are assigned to incoming queries then. If all sessions are used the next is entered in a queue.
A session is created on the AppServer as soon as a user logs in. It is valid as long as the client application is running or until the user logs out. The number of simultaneous database connections on the app server is limited. The number can be set in the configuration file
pappserver.cfg.[LINKDB] MaxConnections=10 MaxTransactions=10
MaxConnections: Defines the maximum number of database commands that can be executed simultaneously.
MaxTransactions: Sometimes a client also opens transactions if several database commands are to be bundled. The maximum number is determined by MaxTransactions. If all of them are used, the client waits until another one becomes free. Transactions are usually used when changes are made to the database.
Only ONE connection from PARTapplicationServer to link database. So the database connection has to be configured only at one place. This is especially interesting if ODBC is used. ODBC is recommended for the AppServer, because it is faster and more stable.
Central login process is on the Server. The login to the DB is omitted when PARTsolutions is launched, because only the AppServer has to be logged in.