SQLite初級操作

#import <Foundation/Foundation.h>

@interface LanOuStudent : NSObject

//名字
@property (nonatomic,retain)NSString *name;
//年齡
@property (nonatomic,assign)NSInteger age;
//性別
@property (nonatomic,retain)NSString *gender;
//學號
@property (nonatomic,assign)NSInteger number;
//圖片的data
@property (nonatomic,retain)NSData *data;

@end

-----------------------------------------------------------------------

#import "LanOuStudent.h"

@implementation LanOuStudent


- (void)dealloc{
    [_name release];
    [_gender release];
    [_data release];
    [super dealloc];
}

@end

#import <Foundation/Foundation.h>
#import <sqlite3.h>
#import "LanOuStudent.h"

@interface SQLiteManager : NSObject

//使用SQLite數據庫步驟
//1.引入libsqlite3.0 框架
//2.在數據庫操作類中  引入<sqlite3.h>頭文件
//注:咱們使用的方法  都在這個類中

//單例的初始化方法
+ (SQLiteManager *)shareManager;

// 插入數據
- (void)insertTableWithStudent:(LanOuStudent *)student;

//刪除數據(根據一個條件刪除)
- (void)deleteWithAge:(NSInteger )age;

//更新數據(根據一個條件來更新)
- (void)updateAge:(NSInteger)age byName:(NSString *)name;

//查詢數據 (根據條件查詢)
- (LanOuStudent *)selectStudentWithName:(NSString *)name age:(NSInteger)age;

// 查詢所有(返回一個數組)

- (NSArray *)selectAllStudents;

@end

-----------------------------------------------------------------------

#import "SQLiteManager.h"

@implementation SQLiteManager

//單例的初始化方法
+ (SQLiteManager *)shareManager
{
    // 靜態區指針
    static SQLiteManager *manager = nil;
    if (manager == nil) {
        manager = [[SQLiteManager alloc] init];
       
        //調用創建表的方法
        [manager createTable];
    }
   
    return manager;
}

//需要在靜態區定義一個指針指向數據庫 (讓這個指針指向對象 從程序開始到結束 一直存在 程序結束後 被系統自動釋放)

static sqlite3 *db =  nil;

//打開數據庫
- (sqlite3 *)openDB
{
    // 判斷數據庫是否存在 如果存在 直接返回
   
    if (db != nil) {
        return db;
    }else
    {
        // 不存在 則創建一個並打開
       
        //獲取當前documents的路徑
        NSString *documents = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
       
        //拼接數據庫文件路徑(拼接的數據庫文件的名字)
        NSString *dbPath = [documents stringByAppendingPathComponent:@"Student.sqlite"];
        NSLog(@"%@",dbPath);
       
        //創建或者打開數據庫
        //參數1 文件的路徑(需要把oc的字符串 轉化成c語言的) dbPath.UTF8String把oc的轉化成c語言
        //參數2 數據庫的地址
        //接收一下返回值  判斷是否打開成功
        int result = sqlite3_open(dbPath.UTF8String, &db);
       
        //SQLITE_OK 可以查表得到錯誤
        if (result == SQLITE_OK) {
            NSLog(@"打開成功");
        }else
        {
            NSLog(@"打開失敗");
        }
        return db;
    }
   
}

//關閉數據庫
- (void)closeDB
{
    int result = sqlite3_close(db);
    //判斷是否關閉成功
    if (result == SQLITE_OK) {
        NSLog(@"關閉成功");
        //把數據庫的指針 重置爲空
        db = nil;
       
    }else
    {
        NSLog(@"關閉失敗");
    }
}

//創建一張表
- (void)createTable
{
    //注意:一定在操作時  先打開數據庫
    //操作完畢  關閉數據庫
   
    //打開數據庫
    db = [self openDB];
   
    //1.寫SQL語句
    NSString *sql = @"create table IF NOT EXISTS lanOuStudent(number integer primary key not null,name text not null,gender text not null,age integer not null,data blob not null)";
    //2.執行sql語句
    //準備與執行語句的操作
   
    int result =  sqlite3_exec(db, sql.UTF8String, NULL, NULL, NULL);
    if (result == SQLITE_OK) {
        NSLog(@"建表成功");
    }else
    {
        NSLog(@"建表失敗");
    }
   
    //關閉數據庫
    [self closeDB];
   
}

// 插入數據
- (void)insertTableWithStudent:(LanOuStudent *)student
{
    //打開數據庫
    db = [self openDB];
    //寫SQL語句
    NSString *sql = @"insert into LanOuStudent (number,name,gender,age,data) values (?,?,?,?,?)";
    //創建一個跟隨指針(指令集)
    sqlite3_stmt *stmt = nil;
    //執行SQL語句
    //預執行函數 需要用跟隨指針 綁定問號 然後一步一步執行(可以判斷SQL是否正確)
    int result = sqlite3_prepare_v2(db, sql.UTF8String, -1, &stmt, NULL);
    if (result == SQLITE_OK) {
       
        // 綁定問號(根據SQL語句 來決定綁定的順序)
        // 注意:綁定的順序 從1開始
        // 參數2 綁定的順序
        // 參數3 要插入的值
        sqlite3_bind_int(stmt, 1, (int)student.number);
        sqlite3_bind_text(stmt, 2, student.name.UTF8String, -1, NULL);
        sqlite3_bind_text(stmt, 3, student.gender.UTF8String, -1, NULL);
        sqlite3_bind_int(stmt, 4, (int)student.age);
       
        // 綁定二進制數據
        // [student.data bytes]  相當於獲取到data數據的內容
        // (int)[student.data length]  相當於獲取到data數據的長度
        sqlite3_bind_blob(stmt, 5, [student.data bytes], (int)[student.data length], NULL);
        //執行綁定的語句
        sqlite3_step(stmt);
       
        NSLog(@"插入成功");
    }else
    {
        NSLog(@"插入失敗");
    }
    //不管插入是否成功  都要釋放跟隨指針
    sqlite3_finalize(stmt);
   
    //關閉數據庫
    [self closeDB];
   
}

/*
 
 //如果有data數據進行插入的話
 //sqlite3_exec 這個函數 會把data數據轉化成字符串存入數據庫
 //如果插入的數據沒有data數據的話 直接用sqlite3_exec 函數 插入數據就行  不用綁定了
 NSString *sql = @"insert into LanOuStudent (number,name,gender,age) values ('%ld','%@','%@','%ld')"
 


- (void)text:(LanOuStudent *)student
{
    NSString *sql = @"insert into LanOuStudent (number,name,gender,age) values ('%ld','%@','%@','%ld')";
    NSString *sqlNew = [NSString stringWithFormat:@"insert into LanOuStudent (number,name,gender,age) values ('%ld','%@','%@','%ld')",student.number,student.name,student.gender,student.age];
}
*/

//刪除數據(根據一個條件刪除)
- (void)deleteWithAge:(NSInteger )age
{
#pragma mark -- 不綁定刪除 需要拼接SQL語句
    //打開數據庫
//    [self openDB];
//    //寫SQL語句
//    NSString *sql = [NSString stringWithFormat:@"delete from lanOuStudent where age > '%ld'",age];
//    //SQL語句
//    int result = sqlite3_exec(db, sql.UTF8String , NULL, NULL, NULL);
//    //判斷一下執行結果
//    if (result == SQLITE_OK) {
//        NSLog(@"刪除成功");
//    }else
//    {
//        NSLog(@"刪除失敗");
//    }
//   //關閉數據庫
//    [self closeDB];
   
#pragma mark -- 通過綁定刪除方法
   
    //打開數據庫
    [self openDB];
    //寫SQL語句
    NSString *sql = @"delete from lanouStudent where age > ?";
    //創建跟隨指針
    sqlite3_stmt *stmt = nil;
    //預執行語句
    int result = sqlite3_prepare_v2(db, sql.UTF8String , -1, &stmt, NULL);
    if (result == SQLITE_OK) {
       
        //綁定問好
        sqlite3_bind_int(stmt, 1, (int)age);
       
        //執行跟隨執行 綁定的語句
        sqlite3_step(stmt);
       
        NSLog(@"刪除成功");
    }else
    {
        NSLog(@"刪除失敗");
    }
    //不管成功與否 都要釋放跟隨指針
    sqlite3_finalize(stmt);
   
    //關閉數據庫
    [self closeDB];
   
}

//更新數據(根據一個條件來更新)
//update lanOuStudent set age = '%ld' where name = '%@'
- (void)updateAge:(NSInteger)age byName:(NSString *)name
{
    //打開數據庫
    [self openDB];
    //寫SQL語句
    NSString *sql = [NSString stringWithFormat:@"update lanouStudent set age = '%ld' where name = '%@'",age,name];
    //執行語句
    int result = sqlite3_exec(db, sql.UTF8String, NULL, NULL, NULL);
    if (result == SQLITE_OK) {
        NSLog(@"更新成功");
    }else
    {
        NSLog(@"更新失敗");
    }
   
    //關閉數據庫
    [self closeDB];
   
}

//查詢數據 (根據條件查詢)
//select name,imageData from lanOuStudent where name = ? and age = ?
- (LanOuStudent *)selectStudentWithName:(NSString *)name age:(NSInteger)age
{
    //打開數據庫
    [self openDB];
    //寫SQL語句
    NSString *sql = @"select * from lanouStudent where name = ? and age = ?";
    //創建跟隨指針
    sqlite3_stmt *stmt = nil;
   
    //創建一個對象
    LanOuStudent *student = [[LanOuStudent alloc] init];
   
    //預執行語句
    int result = sqlite3_prepare_v2(db, sql.UTF8String, -1, &stmt, NULL);
    if (result == SQLITE_OK) {
        //綁定問號
        sqlite3_bind_text(stmt, 1, name.UTF8String, -1, NULL);
        sqlite3_bind_int(stmt, 2, (int)age);
       
        // 查詢時 如果下一行準備好了 返回 SQLITE_ROW 這時可以繼續查詢
        while (sqlite3_step(stmt) == SQLITE_ROW) {
           
            //讀取數據
            //  <#int iCol#> 列數
            //如果你查詢所有的字段的話 那麼這個列數 就根據你創建表的順序一樣
            // 注意: 從0開始
           
            //如果你查詢的是特定字段 那麼這個列數 就要根據你的SQL語句來寫
            //也是從0開
            int number = sqlite3_column_int(stmt, 0);
            char *name = (char *)sqlite3_column_text(stmt, 1);
            char *gender = (char *)sqlite3_column_text(stmt, 2);
            int age = sqlite3_column_int(stmt, 3);
           
            //讀取二進制數據
            NSData *data = [NSData dataWithBytes:sqlite3_column_blob(stmt, 4)  length:sqlite3_column_bytes(stmt, 4)];
           
            //賦值model
            //[NSString stringWithUTF8String:<#(nonnull const char *)#>]; 把c語言字符串轉化成oc字符串
            student.name = [NSString stringWithUTF8String:name];
            student.gender = [NSString stringWithUTF8String:gender];
            student.number = number;
            student.age = age;
            student.data = data;
           
           
        }
       
       
        NSLog(@"成功");
       
    }else
    {
        NSLog(@"失敗");
    }
   
    //釋放跟隨指針
    sqlite3_finalize(stmt);
    //關閉數據庫
    [self closeDB];
    //自動釋放 對象
    return [student  autorelease];
   
   
}

// 查詢所有(返回一個數組)
// select * from lanOuStudent
- (NSArray *)selectAllStudents
{
    //打開數據庫
    [self openDB];
    //寫SQL語句
    NSString *sql = @"select * from lanouStudent";
   
    //創建一個可變數組備用
    NSMutableArray *array = [NSMutableArray array];
   
    //創建跟隨指針
    sqlite3_stmt *stmt = nil;
    //預執行語句
    int result = sqlite3_prepare_v2(db, sql.UTF8String, -1, &stmt, NULL);
    if (result == SQLITE_OK) {
      
       
        while (sqlite3_step(stmt) == SQLITE_ROW) {
            LanOuStudent *student = [[LanOuStudent alloc] init];
           
            //讀取數據
            int number = sqlite3_column_int(stmt, 0);
            char *name = (char *)sqlite3_column_text(stmt, 1);
            char *gender = (char *)sqlite3_column_text(stmt, 2);
            int age = sqlite3_column_int(stmt, 3);
            NSData *data = [NSData dataWithBytes:sqlite3_column_blob(stmt, 4) length:sqlite3_column_bytes(stmt, 4)];
           
            //賦值model
            student.number = number;
            student.name = [NSString stringWithUTF8String:name];
            student.gender = [NSString stringWithUTF8String:gender];
            student.age = age;
            student.data = data;
           
            //添加到數組
            [array addObject:student];

            [student release];

        }
       
        NSLog(@"成功");
    }else
    {
        NSLog(@"失敗");
    }
   
    //釋放跟隨對象
    sqlite3_finalize(stmt);
    //關閉數據庫
    [self closeDB];
    return array;
   
}

@end

-----------------------------------------------------------------------

- (void)viewDidLoad {

    [super viewDidLoad];
    // Do any additional setup after loading the view.
   
    SQLiteManager *manager = [SQLiteManager shareManager];
   
    //插入數據
    LanOuStudent *student = [[LanOuStudent alloc] init];
    student.name = @"王龍";
    student.gender = @"男";
    student.age = 11;
    student.number = 1;
    student.data = UIImagePNGRepresentation([UIImage imageNamed:@"21.jpg"]);
   
    //插入數據
    [manager insertTableWithStudent:student];
   
    //刪除數據
    //[manager deleteWithAge:15];
   
    //更新數據
    [manager updateAge:18 byName:@"王龍"];
   
    //按要求查詢
    //LanOuStudent *stu = [manager selectStudentWithName:@"王龍" age:18];
   
    //查詢你所有
    NSArray *array = [manager selectAllStudents];
   

}