Integrated development of MySQL database operation and Java program

With the development of the Internet, databases have become the core of data storage and management, and MySQL database has also become a very important one. As a popular programming language, Java also has a wide range of applications. Therefore, it is very necessary to integrate the development of MySQL database and Java program.

This article will introduce the basic operations of MySQL database and how to use MySQL database in Java programs.

Basic operations of MySQL database

MySQL is a relational database management system that can store, manage and query data. Before using the MySQL database, we need to install the MySQL database first and create the required databases, data tables, etc.

The following are the basic operations of the MySQL database:

1. Creation and deletion of databases

Create a database:

CREATE DATABASE database_name;

Delete one Database:

DROP DATABASE database_name;

2. Creation and deletion of data tables

Create a data table:

CREATE TABLE table_name (
   column1 datatype, 
   column2 datatype, 
   column3 datatype,
   .....
   columnN datatype
);

Delete a data table:

DROP TABLE table_name;

3. Data insertion, modification, deletion and query

Insert a piece of data:

INSERT INTO table_name (column1, column2, column3, ..., columnN) 
VALUES (value1, value2, value3, ..., valueN);

Modify a piece of data:

UPDATE table_name SET column1 = value1, column2 = value2, ... columnN = valueN WHERE condition;

Delete a piece of data:

DELETE FROM table_name WHERE condition;

Query data:

SELECT column1, column2, ..., columnN FROM table_name WHERE condition;

Using MySQL database in Java program

To use MySQL database in Java program, you need to use the JDBC driver officially provided by MySQL. The following are the steps to use the MySQL database in a Java program:

1. Introducing the JDBC driver for MySQL

Before using the MySQL database in a Java program, you need to introduce the MySQL JDBC driver. You can download the latest JDBC driver from the MySQL official website and add it to the classpath of your Java program.

2. Load the JDBC driver for MySQL

Before using the MySQL database in a Java program, you need to load the JDBC driver for MySQL. You can use the following code to load the JDBC driver for MySQL:

Class.forName("com.mysql.jdbc.Driver");

3. Connecting to the MySQL database

To connect to the MySQL database, you need to specify the connection string, database user name and password of the MySQL database. You can use the following code to connect to the MySQL database:

Connection conn = DriverManager.getConnection("jdbc:mysql://hostname:port/database_name", "username", "password");

Among them, hostname is the host name or IP address where the MySQL database is located, port is the port number where the MySQL database is located, database_name is the name of the database to be connected, username and password are The username and password required to connect to the MySQL database.

4. Execute SQL statements

After successfully connecting to the MySQL database, you can execute the SQL statement. You can use the following code to execute a SQL statement:

Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("SELECT column1, column2, ..., columnN FROM table_name WHERE condition");

Among them, stmt is the created Statement object, and rs is the result set returned after executing the SQL statement.

5. Processing query results

After executing the SQL query statement, the query results need to be processed. You can use the following code to obtain the query results:

while (rs.next()) {
    String column1 = rs.getString("column1");
    String column2 = rs.getString("column2");
    ...
    String columnN = rs.getString("columnN");
    // 处理查询结果
}

Among them, the rs.getString() method can obtain the value of each column in the query results.

6. Close connections and resources

After using the MySQL database, you need to close the database connection and related resources. Connections and other resources can be closed using the following code:

rs.close();
stmt.close();
conn.close();

The above are the basic steps and operations for using a MySQL database in a Java program. By learning the basic operations of the MySQL database and integrating the MySQL database in Java programs, developers can develop high-quality applications more conveniently and efficiently.

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