Alter Cache (EXT)

The Alter Cache statement changes the definition of a cache on a remote table or view. An error is returned if the remote table or view specified does not exist.

Grammar

ALTER CACHE ON {remote_table | view}

[REFERENCING (remote_table_ref[,remote_table_ref]...)]

[REFRESH_INTERVAL {0 | -1 | interval_value [{M, H, D}]}]

[INITIAL_CHECK [ONFIRSTCONNECT | FIRSTUSE | DEFAULT}]

[PERSIST {TEMPORARY | MEMORY | DISK | DEFAULT}]

[ENABLED {YES | TRUE | NO | FALSE}]

[CALL_LIMIT {0 | -1 | max_calls}]

[FILTER (expression)]

where:

remote_table is the name of the remote table cache definition to be modified. The remote table name can be a two-part name: schemaname.tablename. When specifying a two-part name, the specified remote table must be defined in the specified schema, and you must have the privilege to alter objects in the specified schema. When altering a relational cache, remote_table must specify the primary table of the relational cache.

view is the name of the view cache definition to be modified. The view name can be a two-part name: schemaname.viewname. When specifying a two-part name, the specified view must be defined in the specified schema, and you must have the privilege to alter objects in the specified schema. Caches on views are not currently supported in the product.

REFERENCING is an optional clause that specifies the name of the remote table(s) for which a relationship cache is to be created. See “Relational Caches” and “Referencing Clause” for a complete explanation.

REFRESH_INTERVAL is an optional clause that specifies the length of time the data in the cached table can be used before being refreshed. See “Refresh Interval Clause” for a complete explanation.

INITIAL_CHECK is an optional clause that specifies when the driver initially checks whether the data in the cache needs refreshed. See “Initial Check Clause” for a complete explanation.

PERSIST is an optional clause that specifies the life span of the data in the cached table or view. See “Persist Clause” for a complete explanation.

ENABLED is an optional clause that specifies whether the cache is enabled or disabled for use with SQL statements. See “Enabled Clause” for a complete explanation.

CALL_LIMIT is an optional clause that specifies the maximum number of Web service calls that can be used to populate or refresh the cache. See “Call Limit Clause” for a complete explanation.

FILTER is an optional clause that specifies a filter for the primary table to limit the number of rows that are cached in the primary table. See “Filter Clause” for a complete explanation.

NOTE: At least one of the optional clauses must be used. If two or more are specified, they must be specified in the order shown in the grammar description.

Relational Caches

If the Referencing clause is specified, the Alter Cache statement drops the existing cache and any referenced caches and creates a new set of related caches, one for each of the tables specified in the statement. The cache attributes for the existing cache are the default cache attributes for the new relational cache. Any attributes specified in the Alter Cache statement override the default attributes. If the Referencing clause is not specified, the existing cache references, if any, are used.

If the cache being altered is a relational cache, the attributes specified in the Alter Cache statement apply to all of the caches that comprise the relational cache.