Tables are often accessed by the data values contained in one or more columns. To make such accesses efficient, the tables can be indexed by one or more columns. Such an index supports direct access to the table's rows by their data value content. A given table can support multiple indexes. CA Datacom/DB automatically maintains the index as the table's content changes.
Indexes are a performance-only consideration for you, the SQL user. The presence or absence of an index does not enhance or restrict the logical operations supported for a table. CA Datacom/DB also supports a special type of index to control the physical placement of rows to enhance performance. This "clustering index" is automatically the lowest level, no locks are acquired for rows accessed "read only" created by the system if your Database Administrator has selected this space management option.
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