ios sqlite3 curd 小笔记

定义个sqlite3

sqlite3 *_db;

一些方法的说明：

sqlite3          *db 数据库句柄

sqlite3_stmt      *stmt 

sqlite3_open()  打开数据库(没有数据库就创建)

sqlite3_exec()  执行非查询的sql语句

sqlite3_step()  调用sqlite3_prepare方法后sqlite3_step()函数将在记录集中移动

sqlite3_finalize() 释放结果集

sqlite3_close() 关闭数据库

1.创建/打开数据库

-(void)open_sqlite{ NSString *filename = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"test.sqlite"]; int result = sqlite3_open(filename.UTF8String, &_db); if (result == SQLITE_OK) { //create table t_product /** sqlite3_exec(sqlite3*,const char *sql,int (*callback)(void*,int,char**,char**),void *,char **errmsg) **/ //sql 语句 const char *sql = "create table if not exists t_product(p_id integer primary key autoincrement,p_name text,p_number integer);"; char *errorMsg = NULL; int result = sqlite3_exec(_db,sql,NULL,NULL,&errorMsg); if(result == SQLITE_OK){ NSLog(@"create table OK !"); }else{ NSLog(@"create table error：%s",errorMsg); } }else{ NSLog(@"open database error!"); } }

2. 查询数据

- (IBAction)query:(UIButton *)sender { //执行一条p_id名称包含'3'语句 const char *sql = "select p_id, p_name ,p_number from t_product where p_id like ?"; //定义stmt结果集 sqlite3_stmt *stmt = NULL; /** sqlite3_prepare_v2(sqlite3 *db,const char *zSql,int nByte,sqlite3_stmt **ppStmt,const char **pzTail) **/ int result = sqlite3_prepare_v2(_db,sql,-1,&stmt,NULL); if (result == SQLITE_OK) { NSLog(@"prepare OK"); NSString *condition = [NSString stringWithFormat:@"%%%@%%",@"1"]; // 设置占位符的内容 sqlite3_bind_text(stmt,1,condition.UTF8String,-1,NULL); //执行SQL语句，从结果集中取出数据 // int stepResult = sqlite3_step(stmt); while (sqlite3_step(stmt) == SQLITE_ROW) { int pid = sqlite3_column_int(stmt,0); const unsigned char *pname = sqlite3_column_text(stmt,1); int pnumber = sqlite3_column_int(stmt,2); NSLog(@"%d %s %d", pid, pname, pnumber); } }else{ NSLog(@"prepare error"); } } 3.更新数据库

- (IBAction)update:(UIButton *)sender { const char *sql = "insert or replace into t_product (p_id,p_name,p_number) values(10,'product_new',20)"; char *errorMsg = NULL; int result = sqlite3_exec(_db, sql, NULL, NULL, &errorMsg); if (result == SQLITE_OK) { NSLog(@"update data success !"); }else{ NSLog(@"update data error :%s",errorMsg); } } 4.删除某一条数据

- (IBAction)delete:(UIButton *)sender { const char *sql = "delete from t_product where p_id = 10 "; char *errorMsg = NULL; int result = sqlite3_exec(_db, sql, NULL, NULL, &errorMsg); if (result == SQLITE_OK) { NSLog(@"delete data success !"); }else{ NSLog(@"delete data error :%s",errorMsg); } }