Heap Tables

[#1]

Hi,

Can we create reports taking data from heap tables?

Thanks

TR

[Gysbert_Wassenaar]

Heap tables? What are those?

[qlikviewwizard]

Hi ArchanaReddy

Where can we find heap tables?

[awhitfield]

Here you go!

https://msdn.microsoft.com/en-GB/library/hh213609(v=sql.110).aspx

Heaps (Tables without Clustered Indexes)

  SQL Server 2012 

  Other Versions 

• SQL Server 2014
• SQL Server 2016

A heap is a table without a clustered index. One or more nonclustered indexes can be created on tables stored as a heap. Data is stored in the heap without specifying an order. Usually data is initially stored in the order in which is the rows are inserted into the table, but the Database Engine can move data around in the heap to store the rows efficiently; so the data order cannot be predicted. To guarantee the order of rows returned from a heap, you must use the ORDER BY clause. To specify the order for storage of the rows, create a clustered index on the table, so that the table is not a heap.

Note
There are sometimes good reasons to leave a table as a heap instead of creating a clustered index, but using heaps effectively is an advanced skill. Most tables should have a carefully chosen clustered index unless a good reason exists for leaving the table as a heap.