30 | WHERE clause (JPQL / Criteria API) JPQL query that retrieves selective objects from the database. Out of the four optional clauses of JPQL queries, the WHERE clause is definitely the most frequently used. How a WHERE Clause Works The following query retrieves only countries with a population size above a population size p: SELECT c |
28 | 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 |
28 | setLockMode(lockMode)Method javax.persistence.Query Query setLockMode( LockModeType lockMode ) Set the lock mode type to be used for the query execution. Parameters: lockMode - lock mode Returns: the same query instance Throws: IllegalStateException - if the query is found not to be a Java Persistence query language SELECT query or a Criteria API query Since: JPA 2.0 |
28 | getResultList()Method javax.persistence.Query List getResultList() Execute a SELECT query and return the query ... for a Java Persistence query language UPDATE or DELETE statement QueryTimeoutException - if the query execution exceeds the query timeout value set and only the statement is rolled |
28 | getSingleResult()Method javax.persistence.Query Object getSingleResult() Execute a SELECT query that returns ... query language UPDATE or DELETE statement QueryTimeoutException - if the query execution exceeds the query timeout value set and only the statement is rolled back TransactionRequiredException - if a lock |
2 | addSubquery(sub, variableDeclaration, candidateCollectionExpression, parameters)Method javax.jdo.Query void addSubquery( Query sub, String variableDeclaration, String candidateCollectionExpression, String... parameters ) Add a subquery to this query. A subquery is composed as a Query and subsequently attached to a different query (the outer query) by calling this method |
2 | addSubquery(sub, variableDeclaration, candidateCollectionExpression, parameters)Method javax.jdo.Query void addSubquery( Query sub, String variableDeclaration, String candidateCollectionExpression, Map parameters ) Add a subquery to this query. The Map version of the method ... without the leading ":", and the value as the name of the expression in the outer query. If the trimmed expression |
2 | addSubquery(sub, variableDeclaration, candidateCollectionExpression, parameter)Method javax.jdo.Query void addSubquery( Query sub, String variableDeclaration, String candidateCollectionExpression, String parameter ) Add a subquery to this query. The String version of the method ... . Parameters: sub - the subquery to add to this Query variableDeclaration - the name of the variable |
2 | newQuery(language, query)Method javax.jdo.PersistenceManager Query newQuery( String language, Object query ) Create a new Query using the specified language. Parameters: language - the language of the query parameter query - the query, which is of a form determined by the language Returns: the new Query Since: JDO 1.0 |
2 | addSubquery(sub, variableDeclaration, candidateCollectionExpression)Method javax.jdo.Query void addSubquery( Query sub, String variableDeclaration, String candidateCollectionExpression ) Add a subquery to this query. Parameters: sub - the subquery to add to this Query variableDeclaration - the name of the variable in the outer query to bind the results |
