内容简介:生命不止,继续 go go go !!!微信PK10平台开发继续与大家分享,go语言的实战,今天介绍的是如何操作sqlite数据库。何为sqlite3?
生命不止,继续 go go go !!!微信PK10平台开发
继续与大家分享,go语言的实战,今天介绍的是如何操作 sqlite 数据库。
何为sqlite3?
SQLite is a self-contained, high-reliability, embedded, full-featured, public-domain, SQL database engine.
最主要的是,sqlite是一款轻型的数据库
database/sql包
go中有一个database/sql package,我们看看是怎样描述的:
Package sql provides a generic interface around SQL (or SQL-like) databases.
The sql package must be used in conjunction with a database driver
很清晰吧,需要我们自己提供一个database driver。当然,我们可以在github上找到相关的sqlite3的driver,稍后介绍。
下面介绍接个数据相关的操作:
Open
func Open(driverName, dataSourceName string) (*DB, error)
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需要提供两个参数,一个driverName,一个数据库的名。
Prepare
func (db DB) Prepare(query string) ( Stmt, error)
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Prepare creates a prepared statement for later queries or executions.
返回的 *Stmt是什么鬼?
Stmt
Stmt is a prepared statement. A Stmt is safe for concurrent use by multiple goroutines.
func (*Stmt) Exec
准备完成后,就要执行了。
func (s *Stmt) Exec(args ...interface{}) (Result, error)
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Exec executes a prepared statement with the given arguments and returns a Result summarizing the effect of the statement.
返回的Resault是什么鬼?
Result
type Result interface {
// LastInsertId returns the integer generated by the database
// in response to a command. Typically this will be from an
// "auto increment" column when inserting a new row. Not all
// databases support this feature, and the syntax of such
// statements varies.
LastInsertId() (int64, error)
// RowsAffected returns the number of rows affected by an // update, insert, or delete. Not every database or database // driver may support this. RowsAffected() (int64, error)
}
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Query
func (s Stmt) Query(args ...interface{}) ( Rows, error)
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查询,返回的Rows是什么鬼?
Rows
Rows is the result of a query. Its cursor starts before the first row of the result set.
func (rs *Rows) Next() bool
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Next prepares the next result row for reading with the Scan method
func (rs *Rows) Scan(dest ...interface{}) error
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Scan copies the columns in the current row into the values pointed at by dest.
介绍少不多了,下面介绍一个sqlite3的Driver:
mattn/go-sqlite3
sqlite3 driver for go that using database/sql
github地址:
https://github.com/mattn/go-sqlite3执行:
go get -u github.com/mattn/go-sqlite3
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下面要开始我们的实战了!!!!
创建数据库,创建表
//打开数据库,如果不存在,则创建 db, err := sql.Open("sqlite3", "./test.db") checkErr(err) //创建表 sql_table := ` CREATE TABLE IF NOT EXISTS userinfo( uid INTEGER PRIMARY KEY AUTOINCREMENT, username VARCHAR(64) NULL, departname VARCHAR(64) NULL, created DATE NULL ); ` db.Exec(sql_table)
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新建一个数据库叫test.db,并在这个数据库中建一个表,叫做userinfo。
userinfo中包含了四个字段,uid username departname created.
把uid设置为主键,并AUTOINCREMENT,自增。
插入数据
stmt, err := db.Prepare("INSERT INTO userinfo(username, departname, created) values(?,?,?)") checkErr(err) res, err := stmt.Exec("wangshubo", "×××", "2017-04-21") checkErr(err)
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显示Prepare,然后Exec.
接下来,就不再赘述了,我们需要一个基本的 sql 知识。
补充:import中_的作用
官方解释:
To import a package solely for its side-effects (initialization), use the blank identifier as explicit package name:
"lib/math"
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当导入一个包时,该包下的文件里所有init()函数都会被执行。
然而,有些时候我们并不需要把整个包都导入进来,仅仅是是希望它执行init()函数而已。这个时候就可以使用 import
引用该包。最后献上全部代码:
package main
import (
"database/sql"
"fmt"
"time"
_ "github.com/mattn/go-sqlite3"
)
func main() {
//打开数据库,如果不存在,则创建
db, err := sql.Open("sqlite3", "./foo.db")
checkErr(err)
//创建表 sql_table := ` CREATE TABLE IF NOT EXISTS userinfo( uid INTEGER PRIMARY KEY AUTOINCREMENT, username VARCHAR(64) NULL, departname VARCHAR(64) NULL, created DATE NULL ); ` db.Exec(sql_table) // insert stmt, err := db.Prepare("INSERT INTO userinfo(username, departname, created) values(?,?,?)") checkErr(err) res, err := stmt.Exec("wangshubo", "×××", "2017-04-21") 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("wangshubo_new", id) checkErr(err) affect, err := res.RowsAffected() checkErr(err) fmt.Println(affect) // query rows, err := db.Query("SELECT * FROM userinfo") checkErr(err) var uid int var username string var department string var created time.Time for rows.Next() { err = rows.Scan(&uid, &username, &department, &created) checkErr(err) fmt.Println(uid) fmt.Println(username) fmt.Println(department) fmt.Println(created) } rows.Close() // 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)
}
}
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