在SSDT中,我有一个表和列存储索引定义为:
CREATE TABLE [dbo].[FactBillPayTransaction] (
[NaturalKeyText] NVARCHAR (500) NOT NULL,
[RecordEffectiveDateTime] DATETIME2 (7) NOT NULL,
[SourceEffectiveUTCDateTime] DATETIME2 (7) NOT NULL,
[InsertJobRunSequenceNumber] BIGINT NOT NULL,
[LatestUpdateJobRunSequenceNumber] BIGINT NOT NULL,
[InsertDateTime] DATETIME2 (7) NOT NULL,
[LatestUpdateDateTime] DATETIME2 (7) NOT NULL,
[DeleteDateTime] DATETIME2 (7) NULL,
[ChangeControlChecksum] NVARCHAR (32) NOT NULL,
.......More Columns
);
GO
CREATE CLUSTERED COLUMNSTORE INDEX [ci_cs_FactBillPayTransaction]
ON [dbo].[FactBillPayTransaction];
When I generate scripts i get the following for SQL Server 2014:
CREATE TABLE [dbo].[FactBillPayTransaction] (
[NaturalKeyText] NVARCHAR (500) NOT NULL,
[RecordEffectiveDateTime] DATETIME2 (7) NOT NULL,
[SourceEffectiveUTCDateTime] DATETIME2 (7) NOT NULL,
[InsertJobRunSequenceNumber] BIGINT NOT NULL,
[LatestUpdateJobRunSequenceNumber] BIGINT NOT NULL,
[InsertDateTime] DATETIME2 (7) NOT NULL,
[LatestUpdateDateTime] DATETIME2 (7) NOT NULL,
[DeleteDateTime] DATETIME2 (7) NULL,
[ChangeControlChecksum] NVARCHAR (32) NOT NULL,
.......More Columns
);
CREATE CLUSTERED INDEX [ci_cs_FactBillPayTransaction]
ON [dbo].[FactBillPayTransaction]([NaturalKeyText]);
CREATE CLUSTERED COLUMNSTORE INDEX [ci_cs_FactBillPayTransaction]
ON [dbo].[FactBillPayTransaction] WITH (DROP_EXISTING = ON);
这两个创建“索引”命令似乎不正确,为什么它有一个列的引用?
这必须是产品缺陷,但最终结果仍然是正确的。
每个rowstore索引必须至少引用一列,这就是您在生成的第一个CREATE CLUSTERED INDEX语句中引用一列的原因。
生成CREATE CLUSTERED INDEX的最可能原因在于partitioning requirements of columnstore indexes:数据必须是分区对齐的,因此首先需要在分区方案上创建聚簇索引(将每一行分配给它的分区)然后你需要使用DROP_EXISTING=TRUE
子句创建具有相同分区方案的聚簇列存储索引。因此,如果您有一个分区表,那么语法将如下所示:
CREATE CLUSTERED INDEX [ci_cs_FactBillPayTransaction]
ON [dbo].[FactBillPayTransaction]([NaturalKeyText])
ON COLUMNSTORE_PARTITION_SCHEME (NaturalKeyText);
CREATE CLUSTERED COLUMNSTORE INDEX [ci_cs_FactBillPayTransaction]
ON [dbo].[FactBillPayTransaction] WITH (DROP_EXISTING = ON)
ON COLUMNSTORE_PARTITION_SCHEME (NaturalKeyText);
没关系。这不是问题。我的本地数据库版本不支持此功能。目标确实如此。这个陈述实际上做的是创建一个约束,然后再次删除并创建它。