iOS开发——数据持久化Swift篇&（三）SQLite3

SQLite3

使用

 //******************** 5.3 SQLite3存储和读取数据
     func use_SQLite3()
     {
         //声明一个Documents下的路径
         var dbPath = NSHomeDirectory() + "/Documents/SwiftClassDB.sqlite"

         //判断数据库文件是否存在
         if !NSFileManager.defaultManager().fileExistsAtPath(dbPath)
         {
             //获取安装包内数据库路径
             var bundleDBPath:String? = NSBundle.mainBundle().pathForResource("SwiftClassDB", ofType: "sqlite")

             //将安装包内数据库拷贝到Documents目录下
             NSFileManager.defaultManager().copyItemAtPath(bundleDBPath!, toPath: dbPath, error: nil)
         }

         //打开数据库
         let dbOperation = DatabaseOperations(dbPath: dbPath)

         //添加一张表
         dbOperation.createTable();

         //插入一条信息， 通过Person对象来传值
         let person:Person = Person(name: )

         dbOperation.addUser(person)

         //查询
         let personArray:[Person] = dbOperation.readAllUsers()
         println("共搜索到：\(personArray.count) 条数据" )

         //更新
         dbOperation.updateUser("刘明洋", toName: "刘蕙通")

         //删除
         dbOperation.deleteUser("刘蕙通")

         //关闭数据库
         dbOperation.colseDb()

     }

     //******************** 5.4 Core Data
     func use_CoreData()
     {
         //参见工程  LMYCoreData
     }

数据操作

 class DatabaseOperations {

     //不透明指针，对应C语言里面的void *，这里指sqlite3指针
     private var db:COpaquePointer = nil

     //初始化方法打开数据库
     required init(dbPath:String)
     {
          println("db path:" + dbPath)

         //String类的路径，转换成cString
         let cpath = dbPath.cStringUsingEncoding(NSUTF8StringEncoding)

         //打开数据库
         let error = sqlite3_open(cpath!, &db)

         //数据库打开失败处理
         if error != SQLITE_OK {
             sqlite3_close(db)
         }
     }

     deinit{
         self.colseDb()
     }

     //关闭数据库
     func colseDb(){

         sqlite3_close(db)
     }

     //代码创建表
     func createTable() -> Bool{

         //sql语句
         var sql = "CREATE TABLE UserTable(id INTEGER PRIMARY KEY  AUTOINCREMENT NOT NULL, username TEXT NOT NULL, password TEXT NOT NULL, email TEXT, age INTEGER)"

         //执行sql语句
         var execResult = sqlite3_exec(db, sql.cStringUsingEncoding(NSUTF8StringEncoding)!, nil, nil, nil);

         //判断是否执行成功
         if (execResult != SQLITE_OK) {
             return false
         }

         return true
     }

     //插入一条信息
     func addUser(user: Person) -> Bool
     {
         //sql语句
         var sql = "INSERT INTO UserTable (username, password, email, age) VALUES (?, ?, ?, ?);";
         //sql语句转换成cString类型

         var cSql = sql.cStringUsingEncoding(NSUTF8StringEncoding)

         //sqlite3_stmt 指针
         var stmt:COpaquePointer = nil

         //1.编译sql
         let prepare_result = sqlite3_prepare_v2(self.db, cSql!, -, &stmt, nil)

         //判断如果失败，获取失败信息
         if prepare_result != SQLITE_OK {
             sqlite3_finalize(stmt)
             if let error = String.fromCString(sqlite3_errmsg(self.db)) {
                 let msg = "SQLiteDB - failed to prepare SQL: \(sql), Error: \(error)"
                 println(msg)
                 self.alert(msg)
             }
             return false
         }

         let intTran = UnsafeMutablePointer<Int>(bitPattern: -)
         let tranPointer = COpaquePointer(intTran)
         let transient = CFunctionPointer<((UnsafeMutablePointer<()>) -> Void)>(tranPointer)

         //2.bind 绑定参数
         //第2个参数：索引从1开始
         //最后一个参数为函数指针
         sqlite3_bind_text(stmt, , user.name!.cStringUsingEncoding(NSUTF8StringEncoding)!, -, transient);
         sqlite3_bind_text(stmt, , user.password!.cStringUsingEncoding(NSUTF8StringEncoding)!, -, transient);
         sqlite3_bind_text(stmt, , user.email!.cStringUsingEncoding(NSUTF8StringEncoding)!, -, transient);
         sqlite3_bind_int(stmt, , CInt(user.age!));

         //3.step执行
         var 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 let err = String.fromCString(sqlite3_errmsg(self.db)) {
                 let msg = "SQLiteDB - failed to execute SQL: \(sql), Error: \(err)"
                 println(msg)
                 self.alert(msg)
             }
             return false
         }

         //4.finalize
         sqlite3_finalize(stmt);

         return true
     }

     //查询
     func readAllUsers() -> [Person]{

         //声明一个Person对象数组（查询的信息会添加到该数组）
         var usersArr = [Person]()

         //查询sql语句
         var sql = "SELECT * FROM UserTable;";

         //sqlite3_stmt 指针
         var stmt:COpaquePointer = nil
         var cSql = sql.cStringUsingEncoding(NSUTF8StringEncoding)

         //1.编译sql
         let prepare_result = sqlite3_prepare_v2(self.db, cSql!, -, &stmt, nil)
         if prepare_result != SQLITE_OK {
             sqlite3_finalize(stmt)
             if let error = String.fromCString(sqlite3_errmsg(self.db)) {
                 let msg = "SQLiteDB - failed to prepare SQL: \(sql), Error: \(error)"
                 println(msg)
                 self.alert(msg)
             }
             return usersArr
         }

         //2.step
         while (sqlite3_step(stmt) == SQLITE_ROW) {
             var user = Person()

             //循环 从数据库获取数据，添加到数组中
             let cName = UnsafePointer<CChar>(sqlite3_column_text(stmt, ))
             let cPwd = UnsafePointer<CChar>(sqlite3_column_text(stmt, ))
             let cEmail = UnsafePointer<CChar>(sqlite3_column_text(stmt, ))
             let cAge = sqlite3_column_int(stmt, )

             user.name = String.fromCString(cName)
             user.password = String.fromCString(cPwd)
             user.email = String.fromCString(cEmail)
             user.age = Int(cAge)

             usersArr += [user]
         }

         //3.finalize
         sqlite3_finalize(stmt);

         return usersArr
     }

     //更新一条信息
     func updateUser(name: String , toName:String) -> Bool
     {
         //更新sql语句
         var sql = "update UserTable set username = '\(toName)' where username = '\(name)'";

         //sqlite3_stmt 指针
         var stmt:COpaquePointer = nil
         var cSql = sql.cStringUsingEncoding(NSUTF8StringEncoding)

         //1.编译sql
         let prepare_result = sqlite3_prepare_v2(self.db, cSql!, -, &stmt, nil)

         //判断如果失败，获取失败信息
         if prepare_result != SQLITE_OK {
             sqlite3_finalize(stmt)
             if let error = String.fromCString(sqlite3_errmsg(self.db)) {
                 let msg = "SQLiteDB - failed to prepare SQL: \(sql), Error: \(error)"
                 println(msg)
                 self.alert(msg)
             }
             return false
         }

         //3.step执行
         var 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 let err = String.fromCString(sqlite3_errmsg(self.db)) {
                 let msg = "SQLiteDB - failed to execute SQL: \(sql), Error: \(err)"
                 println(msg)
                 self.alert(msg)
             }
             return false
         }

         //4.finalize
         sqlite3_finalize(stmt);

         return true
     }

     //删除一条信息
     func deleteUser(username: String) -> Bool
     {
         //删除sql语句
         var sql = "delete from UserTable  where username = '\(username)'";

         //sqlite3_stmt 指针
         var stmt:COpaquePointer = nil
         var cSql = sql.cStringUsingEncoding(NSUTF8StringEncoding)

         //1.编译sql
         let prepare_result = sqlite3_prepare_v2(self.db, cSql!, -, &stmt, nil)

         //判断如果失败，获取失败信息
         if prepare_result != SQLITE_OK {
             sqlite3_finalize(stmt)
             if let error = String.fromCString(sqlite3_errmsg(self.db)) {
                 let msg = "SQLiteDB - failed to prepare SQL: \(sql), Error: \(error)"
                 println(msg)
                 self.alert(msg)
             }
             return false
         }

         //3.step执行
         var 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 let err = String.fromCString(sqlite3_errmsg(self.db)) {
                 let msg = "SQLiteDB - failed to execute SQL: \(sql), Error: \(err)"
                 println(msg)
                 self.alert(msg)
             }
             return false
         }

         //4.finalize
         sqlite3_finalize(stmt);

         return true
     }

     //定义一个报警器
     func alert(msg:String) {
         dispatch_async(dispatch_get_main_queue()) {
             let alert = UIAlertView(title: "SQLiteDB", message:msg, delegate: nil, cancelButtonTitle: "OK")
             alert.show()
         }
     }
 }