SQL
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1 #import "ViewController.h" 2 #import <sqlite3.h> 3 #import "DataBaseManager.h" 4 @interface ViewController () 5 6 @end 7 8 @implementation ViewController 9 10 - (void)viewDidLoad { 11 [super viewDidLoad]; 12 /* 13 //获取documents的路径 14 NSString *doctmentsPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0]; 15 //创建数据库路径 16 NSString *sqlPath = [doctmentsPath stringByAppendingPathComponent:@"student.sqlite"]; 17 18 //打开数据库,将文件路径转化为char类型的,二阶指针是指针的地址 19 //数据库指针sqlite3 20 #warning 二阶指针 db 21 sqlite3 *db = nil; 22 NSLog(@"%p",db); 23 sqlite3_open(sqlPath.UTF8String, &db); 24 NSLog(@"%p",db); 25 26 //创建stu表,包含字段s_id,s_name,s_age 27 NSString *sqlStr = @"create table if not exists stu (s_id integer primary key,s_name text ,s_age integer)"; 28 //通过result接受执行结果 29 int result = sqlite3_exec(db, sqlStr.UTF8String, NULL, NULL, NULL); 30 31 NSLog(@"%@",result == SQLITE_OK ? @"建表成功":@"建表失败"); 32 NSLog(@"%@",sqlPath); 33 34 //插入数据insert into 35 NSString *insertSql = @"insert into stu (s_name,s_age) values (‘zhangsan‘,20)"; 36 int resultInsert = sqlite3_exec(db, insertSql.UTF8String, NULL, NULL, NULL); 37 NSLog(@"%@",resultInsert == SQLITE_OK ? @"插入成功":@"插入失败"); 38 39 //更改数据 40 NSString *upSql = @"update stu set s_age = 100 where s_age = 20"; 41 int resultUpData = sqlite3_exec(db, upSql.UTF8String, NULL, NULL, NULL); 42 NSLog(@"%@",resultUpData == SQLITE_OK ? @"更改成功":@"更改失败"); 43 44 //删除数据 45 46 NSString *deleteSql = @"delete from stu"; 47 int deleteResult = sqlite3_exec(db, deleteSql.UTF8String, NULL, NULL, NULL); 48 NSLog(@"%@",deleteResult == SQLITE_OK ? @"删除成功":@"删除失败"); 49 50 //关闭数据库 51 int closeResult = sqlite3_close(db); 52 NSLog(@"%@",closeResult == SQLITE_OK ? @"关闭成功":@"关闭失败"); 53 */ 54 55 56 DataBaseManager *dbManager = [DataBaseManager shareInstance]; 57 //使用自定义DataBaseManager,进行数据库操作 58 //打开数据库 59 [dbManager openDB]; 60 //创建表 61 [dbManager createTable]; 62 [dbManager insertName:@"张全蛋" Age:20]; 63 64 NSArray *stuArray =[dbManager selectAll]; 65 NSLog(@"%@",stuArray); 66 NSArray *nameArray = [dbManager selectWithName:@"张全蛋"]; 67 NSLog(@"张全蛋%@",nameArray); 68 [dbManager closeDBm]; 69 70 71 }
1 #import <Foundation/Foundation.h> 2 3 @interface DataBaseManager : NSObject 4 //单例 5 +(instancetype)shareInstance; 6 //打开数据库 7 -(void)openDB; 8 //创建表 9 -(void)createTable; 10 //插入数据 11 -(void)insertName:(NSString *)name Age:(NSInteger) age; 12 //删除数据 13 -(void)deleteWithName:(NSString *)name; 14 //更新数据 15 -(void)updateTable; 16 //查询数据 17 -(NSArray *)selectAll; 18 -(NSArray *)selectWithName:(NSString *)name; 19 //关闭数据库 20 -(void)closeDBm; 21 @end
1 #import "DataBaseManager.h" 2 #import <sqlite3.h> 3 @interface DataBaseManager() 4 //数据库路径 5 @property (nonatomic,copy)NSString *sqlPath; 6 7 @end 8 9 @implementation DataBaseManager 10 //单例 11 +(instancetype)shareInstance 12 { 13 static DataBaseManager *manager = nil; 14 //两种方式创建单例 15 //1.这种方式在工程的整个生命周期只被执行一次,一直到工程关闭被释放 16 static dispatch_once_t onceToken; 17 dispatch_once(&onceToken,^{ 18 manager = [[DataBaseManager alloc] init]; 19 }); 20 // //2.第二种方法 21 // if (manager == nil) { 22 // manager = [[DataBaseManager alloc] init]; 23 // } 24 return manager; 25 } 26 //重写getter方法 27 -(NSString *)sqlPath 28 { 29 //if判断避免每次都进行创建 30 if (_sqlPath == nil) { 31 _sqlPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0] stringByAppendingPathComponent:@"student.sqlite"]; 32 } 33 return _sqlPath; 34 } 35 //由于数据库的表指针全局都要用,所以定义为全局变量 36 static sqlite3 *db = nil; 37 //打开数据库 38 -(void)openDB 39 { 40 #warning 如果sqlPath写成实例变量的形式则不会走getter方法, 41 int result = sqlite3_open(self.sqlPath.UTF8String, &db); 42 NSLog(@"%@",result == SQLITE_OK ?@"打开成功":@"打开失败"); 43 } 44 //创建表 45 -(void)createTable 46 { 47 //创建表的SQL 48 #warning 要把类型放前边,约束放后边 如果把主键约束放前边,integer放后边会出错. 49 NSString *sqlString = @"create table if not exists stu(s_id integer primary key autoincrement,s_name text,s_age integer)"; 50 //执行SQL 51 int result = sqlite3_exec(db, sqlString.UTF8String, NULL, NULL, NULL); 52 NSLog(@"%@", result == SQLITE_OK ?@"建表成功": @"建表失败"); 53 } 54 //插入数据 55 -(void)insertName:(NSString *)name Age:(NSInteger) age; 56 { 57 NSString *sqlString = [NSString stringWithFormat:@"insert into stu (s_name,s_age) values (‘%@‘,‘%ld‘)",name,age]; 58 int result = sqlite3_exec(db, sqlString.UTF8String, NULL, NULL, NULL); 59 NSLog(@"%@", result == SQLITE_OK ?@"插入成功": @"插入失败"); 60 } 61 //删除数据 62 -(void)deleteWithName:(NSString *)name 63 { 64 NSString *sqlString = [NSString stringWithFormat:@"delete from stu where s_name = ‘%@‘",name]; 65 int result = sqlite3_exec(db, sqlString.UTF8String, NULL, NULL, NULL); 66 NSLog(@"%@", result == SQLITE_OK ?@"删除成功": @"删除失败"); 67 } 68 //更新数据 69 -(void)updateTable 70 { 71 NSString *sqlString = @"updata stu set s_age = 10 "; 72 int result = sqlite3_exec(db, sqlString.UTF8String, NULL, NULL, NULL); 73 NSLog(@"%@", result == SQLITE_OK ?@"更新成功": @"更新失败"); 74 75 } 76 77 //查询数据 78 -(NSArray *)selectAll 79 { 80 NSMutableArray *array =[NSMutableArray new]; 81 //查询SQL语句 82 NSString *sqlString = @"select * from stu"; 83 //执行查询 84 85 //stmt伴随指针 86 sqlite3_stmt *stmt = nil; 87 //先创建伴随指针,再进行预执行,stmt指向的是step将要执行的语句 88 int result = sqlite3_prepare(db, sqlString.UTF8String, -1, &stmt, NULL); 89 if (result == SQLITE_OK) { 90 //预执行成功,条件循环取出所有数据 91 while (sqlite3_step(stmt) == SQLITE_ROW) { 92 //第二个参数是指第几列 93 NSInteger s_id = sqlite3_column_int(stmt, 0); 94 //NSString *name = [NSString stringWithUTF8String:sqlite3_column_text(stmt, 1)]; 95 //上面的写法报黄,下面的写法没问题 96 NSString *name = [NSString stringWithUTF8String:(const char *)sqlite3_column_text(stmt, 1)]; 97 98 NSInteger age = sqlite3_column_int(stmt, 2); 99 //由于s_id,age不是对象类型的,所以需要用@()这种形式强转 100 NSDictionary *studentDic = [NSDictionary dictionaryWithObjectsAndKeys:@(s_id),@"s_id",name,@"s_name",@(age),@"s_age", nil]; 101 [array addObject:studentDic]; 102 } 103 //释放伴随指针 104 sqlite3_finalize(stmt); 105 //返回数组 106 return array; 107 } 108 109 return nil; 110 } 111 -(NSArray *)selectWithName:(NSString *)name 112 { 113 NSMutableArray *array = [NSMutableArray array]; 114 //SQL语句 115 NSString *sqlString = @"select * from stu where s_name = ?"; 116 //预执行 117 //伴随指针 118 sqlite3_stmt *stmt = nil; 119 int result = sqlite3_prepare(db, sqlString.UTF8String, -1, &stmt, NULL); 120 if (result == SQLITE_OK) { 121 //预执行成功,绑定参数 bind 122 //sqlite3_column查询获得数据,列数从0开始 123 //第二个参数:sqilit3_bind_绑定参数,表示第几个"?",第三个参数是绑定的参数 124 sqlite3_bind_text(stmt, 1, name.UTF8String, -1, NULL); 125 while (sqlite3_step(stmt) == SQLITE_ROW) { 126 //第二个参数是指第几列 127 NSInteger s_id = sqlite3_column_int(stmt, 0); 128 //NSString *name = [NSString stringWithUTF8String:sqlite3_column_text(stmt, 1)]; 129 //上面的写法报黄,下面的写法没问题 130 NSString *name = [NSString stringWithUTF8String:(const char *)sqlite3_column_text(stmt, 1)]; 131 132 NSInteger age = sqlite3_column_int(stmt, 2); 133 //由于s_id,age不是对象类型的,所以需要用@()这种形式强转 134 NSDictionary *studentDic = [NSDictionary dictionaryWithObjectsAndKeys:@(s_id),@"s_id",name,@"s_name",@(age),@"s_age", nil]; 135 [array addObject:studentDic]; 136 } 137 138 } 139 //释放伴随指针 140 sqlite3_finalize(stmt); 141 return array; 142 } 143 //关闭数据库 144 -(void)closeDBm 145 { 146 int result = sqlite3_close(db); 147 NSLog(@"%@", result == SQLITE_OK ?@"关闭成功": @"关闭失败"); 148 149 } 150 @end
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