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");}
}

- (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);}
}

- (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);}
}