SQLite-OC

-(void)openSqlite:(NSString *)sqliteName{     if (!sqliteName || sqliteName.length <= 0) {         NSAssert(sqliteName, @"sqliteName  is null");     }     if (!db) {         NSString *basePath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];          NSString *path = [basePath stringByAppendingPathComponent:sqliteName];         NSLog(@"sqlite 存放位置:%@",path);         //打开数据库,若存在则打开;反之不存在就创建一个数据库再打开         int result = sqlite3_open([path UTF8String], &db);         if (result == SQLITE_OK) {             NSLog(@"数据库打开成功");             return;         } else {             NSLog(@"数据库打开失败");          }      } }

创建表 & 删除表（表结构）

- (BOOL)createTable{     NSString *sql = @"create table if not exists 'student' ('number' integer primary key autoincrement not null,'name' text,'sex' text,'age' integer, 'score' integer default 0);";     char *error = NULL;     int result = sqlite3_exec(db, [sql UTF8String], nil, nil, &error);     return (result == SQLITE_OK); } -(void)dropTable{     NSString *sql = @"DROP TABLE if EXISTS student;";     char *error = NULL;     int ret = sqlite3_exec(db,[sql UTF8String],NULL,NULL,&error);     if (ret == SQLITE_OK) {         NSLog(@"删除表格成功");     } else {         NSLog(@"删除失败:%s",error);     } } 

表的增删改查

- (void)insertData{     NSString *sql = @"INSERT INTO student (name,sex, age,score) VALUES ('yy','1',28,99);";     char *error = NULL;      int ret = sqlite3_exec(db, [sql UTF8String], NULL, NULL, &error);     if (ret == SQLITE_OK) {         NSLog(@"插入成功");     } else {         NSLog(@"插入失败:%s",error);     } } - (void)deleteData{     NSString *sql = @"DELETE FROM student WHRER number = 1;";     int ret = sqlite3_exec(db, [sql UTF8String], NULL, NULL, NULL);     if (ret == SQLITE_OK) {         NSLog(@"删除成功");     } else {         NSLog(@"删除失败");     } } - (void) selectData{     NSString *sql = @"SELECT name,score FROM student;";     sqlite3_stmt *stmt;     int ret = sqlite3_prepare_v2(db,[sql UTF8String],-1,&stmt,NULL);     if (ret == SQLITE_OK) {         // 查询成功 遍历结果集         while (sqlite3_step(stmt) == SQLITE_ROW) {              const unsigned char *name = sqlite3_column_text(stmt, 0);             NSInteger score = sqlite3_column_int(stmt, 1);             NSLog(@"%@ 分数 %ld",[NSString stringWithUTF8String:(const char *)name],(long)score);         }      } else {         NSLog(@"查询失败");      } }

解决打印乱码问题
Sending 'const unsigned char *' to parameter of type 'const char * _Nonnull' converts between pointer

强制转化


const unsigned char *name = sqlite3_column_text(stmt, 0);
NSInteger score = sqlite3_column_int(stmt, 1);
NSLog(@"%@ 分数 %ld",[NSString stringWithUTF8String:(const char *)name],(long)score);


文章来源: SQLite-OC