JDBC (Java DataBase Connectivity, java database connection) is a Java API used to execute SQL statements. The JDBC API provides a standard interface for interacting with any relational database management system (RDBMS).
The JDBC API contains the following main components:
1.JDBC Driver (JDBC Driver)
2 .Connection (connection)
3.Statement (statement)
4.ResultSet (result set)
Let’s briefly introduce its components to you.
JDBC Driver
A JDBC driver is a set of Java classes that implement the JDBC interface to interact with a specific database. Almost all database vendors (such as MySQL, Oracle, Microsoft SQL Server) provide JDBC drivers. For example, MySQL provides a JDBC driver called MySQL Connection/J, which allows you to use a MySQL database through the standard JDBC API.
There are three types of JDBC drivers, including JDBC native API driver, JDBC-net driver and JDBC driver.
The JDBC driver is written in pure Java. It converts JDBC calls into MySQL-specific calls and sends the calls directly to a specific database. To use the JDBC driver, you need to include the driver JAR file in your application. MySQL Connector/J is a JDBC driver.
Connection
The first and most important component of JDBC is the Connection object. In a Java application, the JDBC driver is loaded first and then the connection to the database is established. Through the Connection object, you can interact with the database, for example, create a Statement to perform SQL queries on the table. You can open multiple database connections at once.
Statement
to execute SQL query, such asSELECT,INSERT,UPDATE,DELETEetc., you can use theStatementobject. You create aStatementobject from aConnectionobject. JDBC provides several types of different uses, such as statementPreparedStatement,CallableStatement.
Result Set
After querying data from the database, you will get a ResultSet object. The ResultSet object provides a set of APIs that allow you to iterate over query results.
The typical process of using JDBC is as follows:
1. First, load the JDBC driver and create a connection to the database.
2. Then, create a Statement and execute the query to get the ResultSet.
3. Next, traverse and process the ResultSet.
4. Close ResultSet, Statement and Connection.
In this article we introduce you to some basic information about JDBC and its main components: JDBC driver, connection, statement and ResultSet. Hope it helps those in need.
The above is the detailed content of What is JDBC. For more information, please follow other related articles on the PHP Chinese website!