标签：prepare update 安装 document nil for key 关闭 file
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 = "zhangsan@163.com" 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() } }
标签：prepare update 安装 document nil for key 关闭 file
原文地址：http://www.cnblogs.com/XYQ-208910/p/6421840.html
