ios - FMDB 在方法中排队读取查询

Question

我想开始使用 FMDatabaseQueue 在我的应用程序中的不同线程中同时运行查询，但我不确定如何在一个方法中实现读取操作。我正在使用此处的示例:http://ccgus.github.io/fmdb/html/Classes/FMDatabaseQueue.html

我如何在方法中实现此代码段，以便它同步运行并返回结果？

FMDatabaseQueue *queue = [FMDatabaseQueue databaseQueueWithPath:aPath];

[queue inDatabase:^(FMDatabase *db) {
    [db executeUpdate:@"INSERT INTO myTable VALUES (?)", [NSNumber numberWithInt:1]];
    [db executeUpdate:@"INSERT INTO myTable VALUES (?)", [NSNumber numberWithInt:2]];
    [db executeUpdate:@"INSERT INTO myTable VALUES (?)", [NSNumber numberWithInt:3]];

    FMResultSet *rs = [db executeQuery:@"select * from foo"];
    while ([rs next]) {
        //…
    }
}];

编辑:澄清一下，我想返回结果集或我自己填充的 NSArray

Answer 1

FMDatabaseQueue 已经同步运行。在返回结果方面，只要创建一个数组对象，然后返回结果即可:

FMDatabaseQueue *queue = [FMDatabaseQueue databaseQueueWithPath:aPath];
NSMutableArray *results = [NSMutableArray array];

[queue inDatabase:^(FMDatabase *db) {
    if (![db executeUpdate:@"INSERT INTO myTable VALUES (?)", @(1)])
        NSLog(@"%s: executeUpdate 1 error: %@", __PRETTY_FUNCTION__, [db lastErrorMessage]);
    if (![db executeUpdate:@"INSERT INTO myTable VALUES (?)", @(2)])
        NSLog(@"%s: executeUpdate 2 error: %@", __PRETTY_FUNCTION__, [db lastErrorMessage]);
    if (![db executeUpdate:@"INSERT INTO myTable VALUES (?)", @(3)])
        NSLog(@"%s: executeUpdate 3 error: %@", __PRETTY_FUNCTION__, [db lastErrorMessage]);

    FMResultSet *rs = [db executeQuery:@"select * from foo"];
    while ([rs next]) {
        // just add your objects to the `results` array
    }
    [rs close];
}];

return results;