Types of Cache Lookup :
None
EntireTable
Found
NotInTTS
FoundAndEmpty
For the master table - EntireTable
For static tables(Like unit tables) - Found
For transaction table - NotInTTS
For static tables (record exists or not example discount table) - FoundAndEmpty
CacheLookup Property :-
None :-
No data is cached or retrieved from the cache for this table.
This property value should be used for tables that are heavily updated or where it's unacceptable to read outdated data.
NotInTTS :-
All successful caching key selects are cached.
When in a transaction (after ttsBegin), no caches made outside the transaction are used. When inside a transaction, the record is read once from database and subsequently from cache. The record is select-locked when read in a transaction, which ensures that the record cached is not updated while the transaction is active.
A typical example of the NotInTTS property is the CustTable in the Microsoft Dynamics AX standard application. It's acceptable to read outdated data from the cache outside a transaction, but when data is used for validation or creating references, it is ensured that the data is real-time.
Found :-
All successful caching key selects are cached. All caching key selects are returned from the cache if the record exists there. A selectforUpdate in a transaction forces reading from the database and replaces the record in the cache.
This is typically used for static (lookup) tables, such as Unit, where the record usually exists.
FoundAndEmpty :-
All selects on caching keys are cached, including selects that are not returning data.
All caching key selects are returned from caching if the record exists there, or the record is marked as nonexistent in the cache. A selectforUpdate in a transaction forces reading from the database and replaces the record in the cache.
An example of FoundAndEmpty record caching is in the Discount table in the Microsoft Dynamics AX standard application. By default, the Discount table has no records. By using a FoundAndEmpty cache on this table, the keys that are queried for but not found are stored in the cache. Subsequent queries for these same non-existent records can be answered from the cache without a round trip to the database.
EntireTable :-
Creates a set-based cache on the server. The entire table is cached as soon as at least one record is selected from the table.
The Found and FoundAndEmpty caches cross transaction boundaries. The NotInTTS cache is newly created inside a transaction. This example, modified for the purposes of this topic, demonstrates how records are retrieved from the cache when the table's CacheLookup property is set to NotInTTS, and the PrimaryIndex property is set to a unique index on the AccountNum field.