org.apache.openjpa.kernel
Interface QueryHints

public interface QueryHints

Standard query hint keys.

Field Summary

static String	HINT_AGGREGATE_LISTENER
static String	HINT_AGGREGATE_LISTENERS
static String	HINT_FILTER_LISTENER
static String	HINT_FILTER_LISTENERS
static String	HINT_IGNORE_FINDER A directive to ignore any cached finder query for find() operation.
static String	HINT_IGNORE_PREPARED_QUERY A directive to ignore any prepared SQL that might have been cached against a JPQL query.
static String	HINT_INVALIDATE_FINDER A directive to invalidate any cached finder query.
static String	HINT_INVALIDATE_PREPARED_QUERY A directive to invalidate any prepared SQL that might have been cached against a JPQL query.
static String	HINT_PARAM_MARKER_IN_QUERY Hints to signal that the JPQL/SQL query string contains a parameter marker ? character.
static String	HINT_RECACHE_FINDER A directive to overwrite a cached finder query by a new query.
static String	HINT_RESULT_COUNT Hint to specify the number of rows to optimize for.
static String	HINT_SUBCLASSES

Field Detail

HINT_SUBCLASSES

static final String HINT_SUBCLASSES

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Constant Field Values

HINT_FILTER_LISTENER

static final String HINT_FILTER_LISTENER

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Constant Field Values

HINT_FILTER_LISTENERS

static final String HINT_FILTER_LISTENERS

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Constant Field Values

HINT_AGGREGATE_LISTENER

static final String HINT_AGGREGATE_LISTENER

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Constant Field Values

HINT_AGGREGATE_LISTENERS

static final String HINT_AGGREGATE_LISTENERS

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Constant Field Values

HINT_RESULT_COUNT

static final String HINT_RESULT_COUNT

Hint to specify the number of rows to optimize for.

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Constant Field Values

HINT_PARAM_MARKER_IN_QUERY

static final String HINT_PARAM_MARKER_IN_QUERY

Hints to signal that the JPQL/SQL query string contains a parameter marker ? character. By default, the query string is parsed to count number of parameters assuming that all ? characters designate a bind parameter. This assumption makes the parse faster.

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Constant Field Values

HINT_INVALIDATE_PREPARED_QUERY

static final String HINT_INVALIDATE_PREPARED_QUERY

A directive to invalidate any prepared SQL that might have been cached against a JPQL query. The target SQL corresponding to a JPQL depends on several context parameters such as fetch configuration, lock mode etc. If a query is executed repeatedly and hence its SQL is cached for faster execution then if any of the contextual parameters change across query execution then the user must supply this hint to invalidate the cached SQL query. The alternative to monitor any such change for automatic invalidation has a constant performance penalty for the frequent use case where a query is repeatedly executed in different persistent context with the same fetch plan or locking.

See Also:

HINT_IGNORE_PREPARED_QUERY, Constant Field Values

HINT_IGNORE_PREPARED_QUERY

static final String HINT_IGNORE_PREPARED_QUERY

A directive to ignore any prepared SQL that might have been cached against a JPQL query. The target SQL corresponding to a JPQL depends on several context parameters such as fetch configuration, lock mode etc. If a query is executed repeatedly and hence its SQL is cached for faster execution then if any of the contextual parameters change across query execution then the user must supply this hint to ignore the cached SQL query for the current execution. This is in contrast with invalidation hint that removes the cached version from cache altogether. The cached SQL is retained and subsequent execution of the same query string without this hint will reuse the cached SQL.

See Also:

HINT_INVALIDATE_PREPARED_QUERY, Constant Field Values

HINT_IGNORE_FINDER

static final String HINT_IGNORE_FINDER

A directive to ignore any cached finder query for find() operation. The cached entry, if any, remains in the cache.

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Constant Field Values

HINT_INVALIDATE_FINDER

static final String HINT_INVALIDATE_FINDER

A directive to invalidate any cached finder query.

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Constant Field Values

HINT_RECACHE_FINDER

static final String HINT_RECACHE_FINDER

A directive to overwrite a cached finder query by a new query.

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Constant Field Values