Caching Functions

Often database tables will be accessed randomly using rec_fetch_main(EQUAL) or the equivalent call to rec_fetch(). If the data in a table is essentially read-only as far as a particular program is concerned and you expect records to be accessed frequently, a program can use the cache functions to reduce the number of calls made to the DBMS. This is done as follows:

• Identify a table to be cached
• Call cache_describe() at the beginning of the program, to set the key size. The key size is usually the total size of the primary key

Note

Records cannot be cached directly in either of these circumstances:

• The table has non-key fields embedded within key fields
• Record access is through a secondary index

Replace calls to:

rec_fetch_main(EQUAL,&table.l,0) 

with:

if (!cache_find(&table.l) && rec_fetch_main(EQUAL, &table.l,0))
  cache_post(&table.l);

• Operational Restrictions
• Operational Refinements