Types of tables: -
- Transparent tables
- Cluster tables
- Pool tables
Transparent tables: - Transparent tables are one to one relationship.
That is if you create one transparent table in the data dictionary, then it’ll
store like only one data base table in the data base.
Cluster table: - This tables are many – one relationship. That is if you create the many clustered tables in DDIC then they will form like a table cluster & store in the data base.
- Buffering isn’t possible for clustered table. From this reason only fetching the data from clustered table take more time.
- Clustered table is suitable when you fetch the fewer amounts of data from more fields.
Pooled table: -
-
Pooled tables are many – one relationship. That means if you create many pooled tables in DDIC, then they will form like a table pool & stored in the data base.
- Pooled tables are suitable when we fetch the large amount of data from fewer fields.Note: - Joins aren’t possible for Clustered & Pooled tables
Index: -
Indexes are used to
improve the performance of the select query. There are two types of indexes.
- Primary index
- Secondary index
Primary index: - Primary index is the primary fields. Without a
primary index we can’t create the data base table. We can place up to 16
primary indexes per table. We can create the primary index only for custom
tables. Not for standard tables.
Secondary index: -Secondary index is possible for other than primary
fields. Without a secondary index we can create the data base table. We can
create up to 9 secondary indexes per a table. We can create secondary index for
both standard & custom tables.
Some of filed names in
T001: –
BUKRS à Company code
BUTXT à Company name
ORT01 à City
LAND1 à Country
Some of field names in
KNA1: -
KUNNR à Customer number
NAME1 à Name
ORT01 à City
LAND1 à Country
SPRAS à Language
Some of the field
names in LFA1 : -
LIFNR à Vendor number
NAME1 à Name
ORT01 à City
LAND1 à Country
SPRAS à Language
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