JDBC

JDBC, Java Database Connectivity, is a Java API that provides a standard way for Java applications to interact with relational databases using SQL. It abstracts database-specific details behind a uniform set of interfaces, allowing code to work with multiple database systems through drivers.

The core elements of JDBC include the Driver, which implements the database-specific communication, and the DriverManager or DataSource, which manage connections. The primary objects used in data access are Connection, Statement (and its subtypes PreparedStatement and CallableStatement), and ResultSet. Error handling is performed through SQLException, and database or result set metadata is accessed via DatabaseMetaData and ResultSetMetaData.

How JDBC works in practice involves loading a JDBC driver, obtaining a Connection from DriverManager or a DataSource, creating a Statement or PreparedStatement to execute SQL, processing results in a ResultSet, and finally closing resources. Transactions are controlled through the Connection, with options for autocommit on or manual commit and rollback as needed.

There are several driver models in JDBC: Type 1 bridging drivers, Type 2 native library drivers, Type 3 network-protocol drivers, and Type 4 pure Java drivers. Type 4 drivers, which communicate directly with the database protocol in pure Java, are the most common in modern environments due to simplicity and portability.

Key features of JDBC include support for prepared statements with parameter binding, batch updates, and stored procedures via CallableStatement, along with transaction management and database metadata access. Connection pooling is typically provided by higher-level frameworks through DataSource rather than directly by JDBC, and proper error handling and resource management are essential for robust database applications.

JDBC is part of the Java Platform, Standard Edition, with the API located in java.sql and javax.sql. Database vendors provide distinct JDBC drivers to enable connectivity, and compatibility is tied to the JDBC version supported by the Java runtime.