Pre-verification of data operations in MySQL database using Go language

Pre-verification is a very critical step in software development. It can help us reduce the occurrence of errors when the program is running and improve the stability and security of the program. When performing data operations on the MySQL database, pre-verification is also very important, because MySQL is a relational database, and any unreasonable operation may lead to data loss or incorrect operation results. This article will introduce how to use Go language to perform pre-verification of data operations in MySQL database.

First, we need to connect to the MySQL database in Go language. Using Go language to operate MySQL database, we can use the officially provided mysql driver. The specific operation process is as follows:

import (
    "database/sql"
    "fmt"

    _ "github.com/go-sql-driver/mysql"
)

func main() {
    // Open up our database connection.
    db, err := sql.Open("mysql", "user:password@tcp(127.0.0.1:3306)/database")
    if err != nil {
        log.Fatal(err)
    }

    // Verify the connection with the Ping() method.
    if err := db.Ping(); err != nil {
        log.Fatal(err)
    }

    // Do something with the newly opened connection here.
    // ...
}

In the above code, we first use the sql.Open() function to connect to the MySQL database, which includes the user name, password, and MySQL server that need to be connected. IP address and port number, as well as the name of the database to connect to. Then, we use the db.Ping() method to verify whether the connection is successful. If the connection fails, an error message will be printed and the program will exit.

Next, we need to classify pre-verification. According to common operation types, pre-verification can be divided into the following categories:

1. Connection verification
2. Verification for insertion, modification, deletion and other operations
3. Query Parameter verification

The first type of pre-verification is relatively simple. In the above code, we have already verified the connection. If the connection is successful, it means that it has passed the verification.

The second type of pre-verification is generally performed before inserting, modifying, deleting and other operations. The specific verification method is determined according to actual needs. The following is a simple example:

func insertData(db *sql.DB, username string, password string) error {
    // Ensure username and password are not empty.
    if len(username) == 0 || len(password) == 0 {
        return errors.New("username and password are required")
    }

    // In the real world, ensure the username doesn't exist before creating a new user.
    if userExists(db, username) {
        return errors.New("user already exists")
    }

    // Perform the insert operation.
    _, err := db.Exec("INSERT INTO users (username, password) VALUES (?, ?)", username, password)
    if err != nil {
        return err
    }

    return nil
}

func userExists(db *sql.DB, username string) bool {
    // Prepare the SQL statement.
    stmt, err := db.Prepare("SELECT count(*) FROM users WHERE username = ?")
    if err != nil {
        return false
    }
    defer stmt.Close()

    // Execute the SQL statement.
    var count int
    err = stmt.QueryRow(username).Scan(&count)
    if err != nil {
        return false
    }

    return count > 0
}

In the above example, we define a function named insertData(), which first verifies whether the entered username and password are Empty, then call the userExists() function to verify whether the user name already exists. If the username already exists, this function will return an error message. If all validations pass, this function performs the insert operation. userExists() The function verifies whether the given username already exists in the database, and returns true if it exists, otherwise it returns false.

The third type of pre-validation is to verify the parameters when querying. This method is very useful because it can help us prevent SQL injection attacks. Here is an example:

func getUsers(db *sql.DB, username string) ([]User, error) {
    // Ensure the username parameter is not empty.
    if len(username) == 0 {
        return nil, errors.New("username is required")
    }

    // Prepare the SQL statement.
    stmt, err := db.Prepare("SELECT * FROM users WHERE username = ?")
    if err != nil {
        return nil, err
    }
    defer stmt.Close()

    // Execute the SQL statement with the given username parameter.
    rows, err := stmt.Query(username)
    if err != nil {
        return nil, err
    }
    defer rows.Close()

    // Collect the query results into a slice of User objects.
    var users []User
    for rows.Next() {
        var u User
        err := rows.Scan(&u.Username, &u.Password)
        if err != nil {
            return nil, err
        }
        users = append(users, u)
    }

    return users, nil
}

In the above example, we define a function called getUsers(), which first verifies whether the entered username is empty, and then Execute the precompiled SQL statement, which will query the user information of all user names in the table named users. Note that we use the stmt.Query() function to pass query parameters through parameter passing. This prevents parameters from being directly spliced ​​into SQL query statements, thereby preventing SQL injection attacks.

Summary

This article introduces the method of using Go language to perform pre-verification of data operations in MySQL database. When operating MySQL database, pre-verification is very important. It can help us reduce the occurrence of errors when the program is running and improve the stability and security of the program. We can divide pre-verification into three categories: connection verification, verification of insertion, modification, deletion and other operations, and verification of query parameters. In practical applications, we can customize our own pre-verification process as needed to improve the robustness and security of the program.

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