Sap Hana - Table
Table of Contents
About
Table data structure in the context of SAP HANA.
Articles Related
Dummy
The dual table is called the dummy table.
select 1 from dummy;
Type
It is possible to change an existing table from one storage type to the other (ALTER TABLE ALTER TYPE).
History
- only insert (no update)
- select as of …
Row vs Column
Storage | Table Size | Update Type |
---|---|---|
Column-based | Big | Bulk |
Row-based | small | Frequent single |
Column store
- Calculations are typically executed on individual or a small number of columns.
- The table is searched based on the values of a few columns.
- The table has a large number of columns.
- The table has a large number of rows and columnar operations are required (aggregate, scan, and so on)
- High compression rates can be achieved because the majority of the columns contain only a few distinct values (compared to the number of rows).
Row store
- The application needs to process only one single record at one time (many selects and /or updates of single records).
- The application typically needs to access the complete record.
- The columns contain mainly distinct values so compression rate would be low.
- Neither aggregations nor fast searching are required.
- The table has a small number of rows (for example, configuration tables).
Virtual
Management
Memory (Load|Unload)
- LOAD <table_name>
- UNLOAD <table_name>
System view
Truncate
Rename
rename table oldTableName to newTableName
Create
Sizing
See the specific structure: