JAVA QUESTIONS

What are the types of statements in JDBC?

The JDBC API has 3 Interfaces,

·        Statement,

·        PreparedStatement,

·        CallableStatement

 The key features of these are as follows:

Statement

This interface is used for executing a static SQL statement and returning the results it produces.

The object of Statement class can be created using Connection.createStatement() method.

PreparedStatement

A SQL statement is pre-compiled and stored in a PreparedStatement object.

This object can then be used to efficiently execute this statement multiple times.

The object of PreparedStatement class can be created using Connection.prepareStatement() method. This extends Statement interface.

CallableStatement

This interface is used to execute SQL stored procedures.

This extends PreparedStatement interface.

The object of CallableStatement class can be created using Connection.prepareCall() method.

What is Connection pooling? What are the advantages of using a connection pool?

Connection Pooling is a technique used for sharing the server resources among requested clients. It was pioneered by database vendors to allow multiple clients to share a cached set of connection objects that provides access to a database.

Getting connection and disconnecting are costly operation, which affects the application performance, so we should avoid creating multiple connection during multiple database interactions. A pool contains set of Database connections which are already connected, and any client who wants to use it can take it from pool and when done with using it can be returned back to the pool.

Apart from performance this also saves you resources as there may be limited database connections available for your application.

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