azure - 使用多个查询条件查询 Windows Azure 表存储

Question

我正在尝试查询 Windows Azure 存储中的表，最初使用 TableQuery.CombineFilters在 TableQuery<RecordEntity>().Where功能如下:

TableQuery.CombineFilters(
    TableQuery.GenerateFilterCondition("PartitionKey",   QueryComparisons.GreaterThanOrEqual, lowDate),
    TableOperators.And,
    TableQuery.GenerateFilterCondition("PartitionKey", QueryComparisons.LessThanOrEqual, lowDate),
    TableQuery.GenerateFilterCondition("PartitionKey", QueryComparisons.Equal, entityId)
));

不幸的是，CombineFilters 最多只允许 2 个查询条件。所以我目前正在这样做:

var tableQuery = new TableQuery<RecordRowEntity>()
            .Where(TableQuery.CombineFilters("PartitionKey", string.Format("(PartitionKey ge '{0}') and (PartitionKey le '{1}') and (RowKey eq '{2}')", low, high, entityId));

还有其他办法吗？我担心我目前的做法很容易受到 Azure Api 工作方式变化的影响。

Answer 1

然后，组合过滤器可以与另一个过滤器组合，根据需要重复多次。请参阅示例“示例 – 查询 PartitionKey=”SamplePK”且 RowKey 大于或等于“5”的所有实体”，地址:https://learn.microsoft.com/en-us/archive/blogs/windowsazurestorage/windows-azure-storage-client-library-2-0-tables-deep-dive#querying .

string pkFilter = TableQuery.GenerateFilterCondition("PartitionKey", QueryComparisons.Equal, "samplePK");

string rkLowerFilter = TableQuery.GenerateFilterCondition("RowKey", QueryComparisons.GreaterThanOrEqual, "5");

string rkUpperFilter = TableQuery.GenerateFilterCondition("RowKey", QueryComparisons.LessThan, "10");

// Note CombineFilters has the effect of "([Expression1]) Operator (Expression2]), as such passing in a complex expression will result in a logical grouping.
string combinedRowKeyFilter = TableQuery.CombineFilters(rkLowerFilter, TableOperators.And, rkUpperFilter);

string combinedFilter = TableQuery.CombineFilters(pkFilter, TableOperators.And, combinedRowKeyFilter);

// OR 
string combinedFilter = string.Format("({0}) {1} ({2}) {3} ({4})", pkFilter, TableOperators.And, rkLowerFilter, TableOperators.And, rkUpperFilter);
TableQuery query = new TableQuery().Where(combinedFilter);