介绍
一、sqlite是纯C语言中底层的数据库，在OC和Swift中都是经常使用的数据库，在开发中，可以使用代码创建数据库，可以使用图形化界面创建数据库。例如SQLiteManager、SQLiteStudio等
二、我使用SQLiteStudio创建的数据库到桌面，然后导出到桌面，再拖到项目中，最后通过代码拷贝到Documens下进行操作，并获取数据库路径
Person.swift
// Person.swift
// swiftDemo
//
// Created by 夏远全 on 2017/2/20.
// Copyright ? 2017年 夏远全. All rights reserved.
//
import UIKit
class Person: NSObject {
var name:String?
var password:String?
var email:String?
var age:Int?
}
DatabaseOperation.swift
(1)打开数据库
//不透明指针，对应C语言中的void *,这里指sqlit3指针
private var db:OpaquePointer? = nil
//初始化方法打开数据库
required init(dbPath:String) {
print("db path:" + dbPath)
//String类的路径，转换成cString
let cpath = dbPath.cString(using: .utf8)
//打开数据库
let error = sqlite3_open(cpath!,&db)
//数据库打开失败
if error != SQLITE_OK {
sqlite3_close(db)
}
}
(2)关闭数据库
//关闭数据库
deinit {
self.closeDB()
}
func closeDB() -> Void {
sqlite3_close(db)
}
(3)创建表
//创建表
func creatTable() -> Bool {
//sql语句
let sql = "CREATE TABLE UserTable(id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,username TEXT NOT NULL, password TEXT NOT NULL,email TEXT NOT NULL,age INTEGER)"
//执行sql语句
let excuResult = sqlite3_exec(db, sql.cString(using: .utf8), nil, nil, nil)
//判断是否执行成功
if excuResult != SQLITE_OK {
return false
}
return true
}
(4)插入数据
//插入数据
func addUser(user:Person) -> Bool {
//sql语句
let sql = "INSERT INTO UserTable(username,password,email,age) VALUES(?,?,?,?);";
//sql语句转换成cString类型
let cSql = sql.cString(using: .utf8)
//sqlite3_stmt指针
var stmt:OpaquePointer? = nil
//编译
let prepare_result = sqlite3_prepare_v2(self.db, cSql!, -1, &stmt, nil)
//判断如果失败，获取失败信息
if prepare_result != SQLITE_OK {
sqlite3_finalize(stmt)
if (sqlite3_errmsg(self.db)) != nil {
let msg = "SQLiteDB - failed to prepare SQL:\(sql)"
print(msg)
}
return false
}
//绑定参数
//第二个参数，索引从1开始
//最后一个参数为函数指针
sqlite3_bind_text(stmt, 1, user.name!.cString(using: .utf8), -1, nil)
sqlite3_bind_text(stmt, 2, user.password!.cString(using: .utf8), -1, nil)
sqlite3_bind_text(stmt, 3, user.email!.cString(using: .utf8), -1, nil)
sqlite3_bind_int(stmt, 4, Int32(Int(user.age!)))
//step执行
let step_result = sqlite3_step(stmt)
//判断执行结果
if step_result != SQLITE_OK && step_result != SQLITE_DONE {
sqlite3_finalize(stmt)
if (sqlite3_errmsg(self.db)) != nil {
let msg = "SQLiteDB - failed to execute SQL:\(sql)"
print(msg)
}
return false
}
//finalize
sqlite3_finalize(stmt)
return true
}
(5)查询数据
//查询数据
func readAllUsers() -> [Person] {
//声明一个Person对象数组（查询的信息会添加到数组中）
var userArr = [Person]()
//查询sql语句
let sql = "SELECT * FROM UserTable;";
//sqlite3_stmt指针
var stmt:OpaquePointer? = nil
let cSql = sql.cString(using: .utf8)
//编译
let prepare_result = sqlite3_prepare_v2(self.db, cSql!, -1, &stmt, nil)
if prepare_result != SQLITE_OK {
sqlite3_finalize(stmt)
if (sqlite3_errmsg(self.db)) != nil {
let msg = "SQLiteDB - failed to prepare SQL:\(sql)"
print(msg)
}
}
//step
while (sqlite3_step(stmt) == SQLITE_ROW) {
let user = Person()
//循环从数据库数据，添加到数组
let cName = UnsafePointer(sqlite3_column_text(stmt, 0))
let cPwd = UnsafePointer(sqlite3_column_text(stmt, 1))
let cEmail = UnsafePointer(sqlite3_column_text(stmt, 2))
let cAge = sqlite3_column_int(stmt, 3)
user.name = String.init(cString: cName!)
user.password = String.init(cString: cPwd!)
user.email = String.init(cString: cEmail!)
user.age = Int(cAge)
userArr += [user]
}
//finalize
sqlite3_finalize(stmt)
return userArr
}
(6)更新数据
//更新数据
func updateUser(name:String,toName:String) -> Bool {
//更新sql语句
let sql = "update UserTable set username = ‘\(toName)‘ where username = ‘\(name)‘";
//sqlite3_stmt指针
var stmt:OpaquePointer? = nil
let cSql = sql.cString(using: .utf8)
//编译sql
let prepare_result = sqlite3_prepare_v2(self.db, cSql!, -1, &stmt, nil)
//判断如果失败，获取失败信息
if prepare_result != SQLITE_OK {
sqlite3_finalize(stmt)
if (sqlite3_errmsg(self.db)) != nil {
let msg = "SQLiteDB - failed to prepare SQL:\(sql)"
print(msg)
}
return false
}
//step执行
let step_result = sqlite3_step(stmt)
//判断执行结果，如果失败，获取失败信息
if step_result != SQLITE_OK && step_result != SQLITE_DONE {
sqlite3_finalize(stmt)
if (sqlite3_errmsg(self.db)) != nil {
let msg = "SQLiteDB - failed to execute SQL:\(sql)"
print(msg)
}
return false
}
//finalize
sqlite3_finalize(stmt)
return true
}
(7)删除数据
//删除数据
func deleteUser(username:String) -> Bool {
//删除sql语句
let sql = "delete from UserTable where username = ‘\(username)‘";
//sqlite3_stmt指针
var stmt:OpaquePointer? = nil
let cSql = sql.cString(using: .utf8)
//编译sql
let prepare_result = sqlite3_prepare_v2(self.db, cSql!, -1, &stmt, nil)
//判断如果失败，获取失败信息
if prepare_result != SQLITE_OK {
sqlite3_finalize(stmt)
if (sqlite3_errmsg(self.db)) != nil {
let msg = "SQLiteDB - failed to prepare SQL:\(sql)"
print(msg)
}
return false
}
//step执行
let step_result = sqlite3_step(stmt)
//判断执行结果，如果失败，获取失败信息
if step_result != SQLITE_OK && step_result != SQLITE_DONE {
sqlite3_finalize(stmt)
if (sqlite3_errmsg(self.db)) != nil {
let msg = "SQLiteDB - failed to execute SQL:\(sql)"
print(msg)
}
return false
}
//finalize
sqlite3_finalize(stmt)
return true
}
(8)复制数据库路径
//将Bundle.main路径下的数据库文件复制到Documents下
class func loadDBPath() -> String {
//声明一个Documents下的路径
let dbPath = NSHomeDirectory() + "/Documents/RWDataTest.db"
//判断数据库文件是否存在
if !FileManager.default.fileExists(atPath: dbPath) {
//获取安装包内是否存在
let bundleDBPath = Bundle.main.path(forResource: "RWDataTest", ofType:"db")!
//将安装包内的数据库到Documents目录下
do {
try FileManager.default.copyItem(atPath: bundleDBPath, toPath: dbPath)
} catch let error as NSError {
print(error)
}
}
return dbPath
}
ViewController.swift测试
// Created by 夏远全 on 2017/1/13.
// Copyright ? 2017年 夏远全. All rights reserved.
//
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
//打开数据库
let path = DatabaseOperations.loadDBPath()
let dbOpearion = DatabaseOperations.init(dbPath:path)
print(path)
//添加一张表
let person:Person = Person()
person.name = "张三"
person.password = "123566"
person.email = "[email protected]"
person.age = 30
//插入一条信息,通过Person对象来传值
let addBool = dbOpearion.addUser(user: person)
print(addBool)
//查询
let personArray:[Person] = dbOpearion.readAllUsers()
print("共搜索到:\(personArray.count) 条数据")
//更新
let updateBool = dbOpearion.updateUser(name: "张三", toName: "李四")
print(updateBool)
//删除
let deleteBool = dbOpearion.deleteUser(username: "李四")
print(deleteBool)
//关闭数据库
dbOpearion.closeDB()
}
}
时间： 2024-08-03 15:10:05