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5.3 SQLite

SQLite is an open source, embedded relational database. It has a self-contained, zero-configuration and transaction-supported database engine. Its characteristics are highly portable, easy to use, compact, efficient and reliable. In most of cases, you only need a binary file of SQLite to create, connect and operate a database. If you are looking for an embedded database solution, SQLite is worth considering. You can say SQLite is the open source version of Access.

SQLite drivers

There are many database drivers for SQLite in Go, but many of them do not support the database/sql interface standards.

The first driver is the only one that supports the database/sql interface standard in its SQLite driver, so I use this in my projects -it will make it easy to migrate my code in the future if I need to.

Samples

We create the following SQL:

CREATE TABLE `userinfo` (
    `uid` INTEGER PRIMARY KEY AUTOINCREMENT,
    `username` VARCHAR(64) NULL,
    `department` VARCHAR(64) NULL,
    `created` DATE NULL
);

An example:

package main

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

func main() {
    db, err := sql.Open("sqlite3", "./foo.db")
    checkErr(err)

    // insert
    stmt, err := db.Prepare("INSERT INTO userinfo(username, department, created) values(?,?,?)")
    checkErr(err)

    res, err := stmt.Exec("astaxie", "研发部门", "2012-12-09")
    checkErr(err)

    id, err := res.LastInsertId()
    checkErr(err)

    fmt.Println(id)
    // update
    stmt, err = db.Prepare("update userinfo set username=? where uid=?")
    checkErr(err)

    res, err = stmt.Exec("astaxieupdate", id)
    checkErr(err)

    affect, err := res.RowsAffected()
    checkErr(err)

    fmt.Println(affect)

    // query
    rows, err := db.Query("SELECT * FROM userinfo")
    checkErr(err)

    for rows.Next() {
        var uid int
        var username string
        var department string
        var created time.Time
        err = rows.Scan(&uid, &username, &department, &created)
        checkErr(err)
        fmt.Println(uid)
        fmt.Println(username)
        fmt.Println(department)
        fmt.Println(created)
    }

    // delete
    stmt, err = db.Prepare("delete from userinfo where uid=?")
    checkErr(err)

    res, err = stmt.Exec(id)
    checkErr(err)

    affect, err = res.RowsAffected()
    checkErr(err)

    fmt.Println(affect)

    db.Close()

}

func checkErr(err error) {
    if err != nil {
        panic(err)
    }
}

You may have noticed that the code is almost the same as in the previous section, and that we only changed the name of the registered driver and called sql.Open to connect to SQLite in a different way.

As a final note on this secton, there is a useful SQLite management tool available: http://sqliteadmin.orbmu2k.de/

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