1.首先判断添加的字段是否存在,如果不存在就添加。
2.代码演示:
(1)判断是否存在,判断之前先导入头文件确保可以调用FMDB的api(#import “FMDatabaseAdditions.h”):
if (![db columnExists:@"新增字段" inTableWithName:@"表名"]){ }
(2)如果不存在,就执行插入操作:
NSString *alertStr = [NSString stringWithFormat:@"ALTER TABLE %@ ADD %@ INTEGER",@"表名",@"新增字段"]; BOOL worked = [db executeUpdate:alertStr]; if(worked){ NSLog(@"插入成功"); }else{ NSLog(@"插入失败"); }
例如:向已存在表(GOODS)中 增加活动商品活动名称(PROMOTION_NAME)
if (![database columnExists:@"PROMOTION_NAME" inTableWithName:@"GOODS"]){ NSString *sqlStr = [NSString stringWithFormat:@"ALTER TABLE %@ ADD %@ VARCHAR(32)",@"GOODS",@"PROMOTION_NAME"]; BOOL worked = [database executeUpdate:sqlStr]; if(worked){ JGLog(@"插入成功"); }else{ JGLog(@"插入失败"); } }