FMDB 动态的添加数据

最新推荐文章于 2020-12-30 20:58:27 发布

原创最新推荐文章于 2020-12-30 20:58:27 发布 · 607 阅读

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本文介绍了一种使用FMDB批量插入数据时，通过动态封装方法简化属性和值添加的过程，包括创建表、组装SQL语句以及处理数据的步骤。

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我们使用FMDB 时，添加数据，时时需要手动添加属性，值，当属性很多时，会过于麻烦
FMDB 有
- (BOOL)executeUpdate:(NSString*)sql withArgumentsInArray:(NSArray *)arguments {
    return [self executeUpdate:sql error:nil withArgumentsInArray:arguments orDictionary:nil orVAList:nil];
}
- (BOOL)executeUpdate:(NSString*)sql withParameterDictionary:(NSDictionary *)arguments {
    return [self executeUpdate:sql error:nil withArgumentsInArray:nil orDictionary:arguments orVAList:nil];
方法，我哦们可以将需要添加的属性，值，做成Key--Value 动态添加，因此需要封装一个方法

// 返回格式：insert into table_name (c1,c2,c3) values (:a,:b,:c);
-(NSString*) assembleInsertSql:(NSDictionary*) tableName
{
    NSArray *datas = [tableName objectForKey:@"data"];

    if([datas count] == 0){

        return nil;
    }
    NSDictionary *record = [datas objectAtIndex:0];// 取出第一条记录，为了拿到列名
    NSArray *columns = [record allKeys];
    NSString *table = [tableName objectForKey:@"tableName"];
    NSString *prefix = [NSString stringWithFormat:@"insert into %@ (", table];
    NSMutableString *middle = [NSMutableString new];
    for(int i=0;i<[columns count];i++){

        NSString *columnName = [columns objectAtIndex:i];// 列名

        if(![@"_id" isEqualToString:columnName]){

            [middle appendString:columnName];

            [middle appendString:@","];
        }
    }
    NSString* cuttedMiddle = [middle substringToIndex:middle.length - 1];

    NSMutableString *suffix = [NSMutableString new];

    [suffix appendString:@") values ("];

    for(int i=0;i<[columns count];i++){

        NSString *columnName = [columns objectAtIndex:i];// 列名

        if(![@"_id" isEqualToString:columnName]){

            [suffix appendString:@":"];

            [suffix appendString:columnName];

            [suffix appendString:@","];

        }
    }
    NSString *cuttedSuffix = [suffix substringToIndex:suffix.length - 1];
    NSMutableString *sql = [NSMutableString new];
    [sql appendString:prefix];
    [sql appendString:cuttedMiddle];
    [sql appendString:cuttedSuffix];

    [sql appendString:@");"];

    return sql;

}

//处理数据
-(void) handleJsonObject:(NSDictionary*) tableName
{
    [db1 open];
    NSString *createC = @"CREATE TABLE Class (Name text,Age integer,Sex text)";
    BOOL e = [db1 executeUpdate:createC];
    if (e) {
        NSLog(@"创建表成功");
    }else
    {
        NSLog(@"创建失败");
    }

    NSString *sql = [self assembleInsertSql:tableName];// 拼装sql语句：insert into table_name (c1,c2,c3) values (:a,:b,:c);
        if(!sql){
        return;// 说明data里无数据，不需要操作数据库
    }

    NSArray *datas = [tableName objectForKey:@"data"];

    for(NSDictionary *data in datas){

        NSMutableDictionary *mutable = [NSMutableDictionary dictionaryWithDictionary:data];

        [mutable removeObjectForKey:@"_id"];

        BOOL result = [db1 executeUpdate:sql withParameterDictionary:mutable];

        if(result){

            NSLog([NSString stringWithFormat:@"%d", [db1 lastErrorCode]], nil);

            NSLog([db1 lastErrorMessage], nil);

        }

    }

    [db close];

}