JDBC presentation

Two-tier and Three-tier Models

Client-server A Java applet or application talks directly to the database. A user's SQL statements are delivered to the database, and the results of those statements are sent back to the user.The database may be located on another machine to which the user is connected via a network.

Client-server-Database server Commands are sent to a "middle tier" of services, which then send SQL statements to the database. The database process the SQL statements and sends the results back to the middle tier, which then sends them to the user. MIS directors find the three-tier model very attractive because the middle tier makes it possible to maintain control over access and the kinds of updates that can be made to corporate data.

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