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How to use JDBC to open the door to the database? Do you know the history of this technology?
Java Database Connectivity (JDBC) is an application programming interface (API) designed for the Java programming language that defines how clients access databases. JDBC is a Java-based data access technology designed to provide convenient database connections. In view of the development of databases, JDBC plays an increasingly important role, especially in the interaction with relational databases, it has become the preferred tool for developers.
JDBC enables developers to easily access and manipulate various databases and has become the core of many enterprise solutions.
JDBC was first released by Sun Microsystems on February 19, 1997 as part of the Java Development Kit (JDK) 1.1. Since then, it has become part of the Java Platform, Standard Edition, and the JDBC classes are included in two Java packages, java.sql and javax.sql.
As JDBC evolved, starting with version 3.1, it was developed in the Java community process, with JSR 54 standardizing JDBC 3.0 (included in J2SE 1.4), and JSR 221 standardizing JDBC 4.0 (included in Java SE 6. ), the latest JDBC 4.3 is the version released in Java SE 9.
Functions and features of JDBC
JDBC is a framework consisting mainly of interface definitions and specifications, which allows multiple methods of implementing these interfaces to run dynamically in the same application. This API provides a mechanism to dynamically load the correct Java package and register it with the JDBC Driver Manager for establishing a JDBC connection. These JDBC connections support the creation and execution of statements, including SQL update statements such as CREATE, INSERT, UPDATE, and DELETE, as well as query statements such as SELECT.
JDBC's diversity enables it to support the management of different databases, whether local or remote.
Types of JDBC Drivers
The JDBC driver is a client adapter that converts Java program requests into a protocol that the database management system (DBMS) can understand. These drivers can be divided into several types:
- Type 1: Native code using the local ODBC driver.
- Type 2: The client calls the local library of the database manufacturer and then communicates with the database through the network.
- Type 3: Pure Java driver that interacts with the database through a server-side intermediary.
- Type 4: Pure Java driver, using the library's native protocol.
With the advancement of technology, the application scope of JDBC is becoming wider and wider. From general data query to complex data analysis and data processing, JDBC is capable of handling all of them, including functions such as CallableStatement for executing stored procedures. Moreover, many database providers have launched their drivers, which makes it convenient for developers to choose.
A practical example of connecting to a database from JDBC
When a Java application requires a database connection, it typically uses the DriverManager.getConnection() method to establish a JDBC connection. The URL here will vary depending on the specific library and JDBC driver, and always begins with the "jdbc:" protocol. For example, if using MySQL, it might be "jdbc:mysql://localhost:3306/dbname".
Starting in Java SE 7, try to use the try-with-resources statement to simplify the code and allow developers to better handle resource release.
Once the connection is established, you can create a Statement to execute SQL queries. However, please note that Connections, Statements, and ResultSets generally consume system resources, especially when connecting to a remote database server. This means that it is critical to call close() immediately to release resources after querying the data, as garbage collection should not be relied upon.
Error Handling and Transaction Management
In JDBC, if a repository operation fails, it throws a SQLException. Usually for such errors, there is little you can do to recover except log the details. It is better to convert SQLException into application domain exception, which will eventually cause transaction rollback and notify consumers. When performing transactions, developers need to ensure that all operations are performed in an atomic manner to ensure data consistency and integrity.
Today, in the face of rapidly changing database requirements, JDBC provides a reliable and efficient solution, whether it is for data query or update operations, developers make full use of its functions in their daily work. In such a data-driven era, it is extremely important for developers to understand the history and future direction of JDBC. How do you think JDBC will further change the way databases are accessed in the future?
