How to create a connection in mysql

The following steps are required to establish a MySQL connection: 1. Import the MySQL client library; 2. Create a connection object; 3. Create a cursor object; 4. Execute the query; 5. Retrieve the results; 6. Close the connection.

How to create a MySQL connection

Establishing a MySQL connection requires the following steps:

1. Import the MySQL client library

First, you need to import the necessary MySQL client library, which provides an interface for the application to communicate with the MySQL database.

For Python:

<code class="python">import mysql.connector</code>

For Java:

<code class="java">import java.sql.*;</code>

2. Create a connection object

Create a connection using the client library Object that will represent a connection to the MySQL database.

For Python:

<code class="python">connection = mysql.connector.connect(
    host="localhost",
    user="root",
    password="my_password",
    database="my_database"
)</code>

• host: The address or hostname of the database server
• user: Has a connection Permission username
• password: User’s password
• database: Name of the database to be connected

For Java:

<code class="java">// 使用 JDBC 创建连接对象
Connection connection = DriverManager.getConnection(
    "jdbc:mysql://localhost:3306/my_database",
    "root",
    "my_password"
);</code>

3. Create a cursor object

Create a cursor object for executing queries and retrieving results.

For Python:

<code class="python">cursor = connection.cursor()</code>

For Java:

<code class="java">Statement statement = connection.createStatement();</code>

4. Execute the query

Use the cursor object to execute the query and put The results are stored in the result set.

For Python:

<code class="python">cursor.execute("SELECT * FROM my_table")</code>

For Java:

<code class="java">ResultSet resultSet = statement.executeQuery("SELECT * FROM my_table");</code>

5. Retrieval results

Traverse the result set and retrieve individual rows.

For Python:

<code class="python">for row in cursor.fetchall():
    print(row)</code>

For Java:

<code class="java">while (resultSet.next()) {
    System.out.println(resultSet.getInt("id"));
}</code>

6. Close the connection

After using the connection, please close the connection object to release resources.

For Python:

<code class="python">cursor.close()
connection.close()</code>

For Java:

<code class="java">statement.close();
connection.close();</code>

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