Learn database functions in Go language and implement addition, deletion, modification and query operations of SQLite data

Learn the database functions in Go language and implement the addition, deletion, modification, and query operations of SQLite data

Go language is a simple, efficient, and highly concurrency programming language that has great advantages in data processing. As one of the main ways of data storage and processing, databases are essential for developers to understand and master database operations. In this article, we will learn the database functions in the Go language and use the SQLite database to implement data addition, deletion, modification and query operations.

First, we need to import the database driver and sqlite3 package provided by the Go language. Add the following code to the code:

import (
    "database/sql"
    _ "github.com/mattn/go-sqlite3"
)

In this code, we use the go-sqlite3 package as the driver for the SQLite database.

Next, we need to create a database connection. Use the sql.Open() function to create a database connection. The code is as follows:

db, err := sql.Open("sqlite3", "./test.db")
if err != nil {
    log.Fatal(err)
}
defer db.Close()

In this code, we open a SQLite database named test.db and assign the connection to the variable db. Additionally, we use the defer keyword to ensure that the database connection is closed after the program ends.

Now, we have connected to the SQLite database and can perform add, delete, modify and query operations.

First, let us implement the data insertion operation. We can use the Exec() function to execute the INSERT statement. The code is as follows:

stmt, err := db.Prepare("INSERT INTO user(name, age) values(?, ?)")
if err != nil {
    log.Fatal(err)
}

_, err = stmt.Exec("Alice", 28)
if err != nil {
    log.Fatal(err)
}

stmt.Close()

In this code, we first use the Prepare() function to prepare a SQL statement to be executed, and then use the Exec() function to execute it. this SQL statement. After execution, we will get the execution results and possible error messages.

Next, let’s implement the data query operation. We can use the Query() function to query the database. The code is as follows:

rows, err := db.Query("SELECT * FROM user")
if err != nil {
    log.Fatal(err)
}
defer rows.Close()

for rows.Next() {
    var name string
    var age int
    err = rows.Scan(&name, &age)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println(name, age)
}

err = rows.Err()
if err != nil {
    log.Fatal(err)
}

In this code, we first use the Query() function to query the database and assign the query results to the variable rows. Then, we use the rows.Next() and rows.Scan() functions to read the query results row by row and write the data into the corresponding variables. After the read is complete, we use the rows.Err() function to check if an error occurred.

Next, let’s implement the data modification and deletion operations. We can use the Exec() function to execute UPDATE and DELETE statements. The code is as follows:

stmt, err = db.Prepare("UPDATE user SET age=? WHERE name=?")
if err != nil {
    log.Fatal(err)
}

_, err = stmt.Exec(30, "Alice")
if err != nil {
    log.Fatal(err)
}

stmt.Close()

stmt, err = db.Prepare("DELETE FROM user WHERE age=?")
if err != nil {
    log.Fatal(err)
}

_, err = stmt.Exec(30)
if err != nil {
    log.Fatal(err)
}

stmt.Close()

In this code, we first use the Prepare() function to prepare the SQL statement to be executed, and then use the Exec() function Execute SQL statements. We can use question mark placeholders to set the value of parameters when executing UPDATE and DELETE statements.

So far, we have learned the database functions in the Go language and implemented the data addition, deletion, modification and query operations of the SQLite database. In actual development, we can further optimize the code according to specific needs and handle possible exceptions. I hope this article can be helpful to you when learning database operations in Go language.

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