87 | Iterating over large result set with one query by running the query with a hint "objectdb.result-fetch" set to "LAZY". Another option is to use ... with one query by running the query with a hint "objectdb.result-fetch" set to "LAZY". That was first thing I ... . for (int page=0; page < resultCount; page+=pageSize) { Query q = em.createQuery("query |
21 | WHERE clause (JPQL / Criteria API) objects to the SELECT clause for collecting as query results, the WHERE clause gets an opportunity ... evaluates to TRUE are passed to the SELECT clause and then collected as query results. WHERE Predicate ... JPQL query that retrieves selective objects from the database. Out of the four optional clauses |
21 | Index DefinitionQuerying without indexes requires iteration over entity objects in the database one by ... the iteration can be avoided and complex queries over millions of objects can be executed quickly ... ; : } Indexes in Queries ObjectDB manages a BTree for every index. A BTree is an ordered map data |
21 | javax.persistence.criteria.CriteriaQuery> distinct(boolean distinct) Specify whether duplicate query results will be eliminated. Specify whether duplicate query results will be eliminated. A true value will cause duplicates to be eliminated ... must be eliminated from the query result or whether they must be retained Returns: the modified |
20 | javax.persistence.TypedQuery and the transaction is rolled back Since: JPA 1.0 int getFirstResult() The position of the first result the query object was set to retrieve. The position of the first result the query object was set to retrieve ... result Since: JPA 2.0 FlushModeType getFlushMode() Get the flush mode in effect for the query execution |
20 | Logical Operators in JPQL and Criteria APILogical operators in JPQL and in JPA criteria queries enable composition of complex JPQL boolean ... , the JDO Query Language). ObjectDB supports both forms. Binary AND (&&) Operator The following query ... the result is FALSE, because one FALSE operand is sufficient for a FALSE result. If one operand is NULL |
2 | setUnmodifiable()Method javax.jdo.Query void setUnmodifiable() The unmodifiable flag, when set, disallows further modification of the query, except for specifying the range, result class, and ignoreCache option. The unmodifiable flag can also be set in metadata. Since: JDO 2.0 |
2 | isUnmodifiable()Method javax.jdo.Query boolean isUnmodifiable() The unmodifiable flag, when set, disallows further modification of the query, except for specifying the range, result class, and ignoreCache option. Returns: the current setting of the flag Since: JDO 2.0 |
2 | setGrouping(group)Method javax.jdo.Query void setGrouping( String group ) Set the grouping expressions, optionally including a "having" clause. When grouping is specified, each result expression must either be an expression contained in the grouping, or an aggregate evaluated once per group. Parameters: group |
2 | deletePersistentAll()Method javax.jdo.Query long deletePersistentAll() Deletes all the instances of the candidate class that pass the filter. Returns the number of instances of the candidate class that were deleted ... the cache as a result of executing one of the deletePersistentAll methods undergo life cycle changes as |
