8) SQL & JDBC Lesson

What is the JDBC Life Cycle?

4 min to complete · By Ryan Desmond

Contents

  1. Introduction
  2. Summary: What is the JDBC Connection
    1. JDBC Life Cycle

Java applications that use a database connection and the JDBC API have a distinct life cycle.

The figure shows the six stages in the life cycle of a JDBC application:

A diagram of the JDBC life cycle

The list below explains each step of the life cycle.

Steps of the JDBC Life Cycle

  1. The first step in a JDBC application is to load the JDBC driver and initialize it. The JDBC driver is loaded by calling the Class.forName().newInstance() method. The JDBC driver is assumed to be in the CLASSPATH.

  2. After loading the JDBC driver, the JDBC application uses the JDBC API to communicate with the database. To do this, the application needs to open a connection to the database using the connect() method of the Driver class. A database connection can be opened only by authenticating with the database. The authentication information can be passed in two different ways: as separate parameters to the connect() method or in the parameter of the  connect() method. This depends on the JDBC driver implementation. The database connection can be stored in the Java class and reused at any point to interact with the database as long as the connection is alive.

  3. After obtaining a database connection, the JDBC application can use the Statement, PreparedStatement, or CallableStatement objects to execute SQL statements. The PreparedStatement and CallableStatement are unique purpose statement interfaces inherited from the Statement interface. The JDBC driver implements these interfaces to provide the underlying functions. The database connection can create the Statement, PreparedStatement, and CallableStatement. Any number of Statement, PreparedStatement, and CallableStatement objects can be created from a live database connection.

  4. After creating a Statement, PreparedStatement, or CallableStatement, SQL statements such as inserts, updates, and queries can be executed using the relevant methods provided in the Statement, PreparedStatement, and CallableStatement interfaces.

  5. If an SQL statement query is executed, the ResultSet and ResultSetMetaData interfaces can be used by the JDBC application to retrieve the data from the database.

  6. The final stage in the JDBC application is the closing of the database connection. Closing the database connection using the "close()" method of the Connection object frees up expensive resources on the database.

Summary: What is the JDBC Connection

  • Many Java applications use a database connection and JDBC API
  • These applications have a six-stage connection process
  • The JDBC lifecycle involves establishing a connection to a database, creating and executing SQL statements, processing results, and finally, closing the connection to release resources.

JDBC Life Cycle

  1. Load the JDBC driver
  2. Open a database connection
  3. Create a Statement/PreparedStatement/CallableStatement
  4. Execute SQL statements
  5. Retrieve and potentially process the results of any SQL query
  6. Close database connection
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