org.hibernate.criterion: public interface: Projection

org.hibernate.criterion
public interface: Projection [javadoc | source]

All Implemented Interfaces:
Serializable

All Known Implementing Classes:
CountProjection, AliasedProjection, AvgProjection, PropertyProjection, AggregateProjection, Property, IdentifierProjection, ProjectionList, RowCountProjection, SimpleProjection, SQLProjection, Distinct

An object-oriented representation of a query result set projection in a Criteria query. Built-in projection types are provided by the Projections factory class. This interface might be implemented by application classes that define custom projections.

Also see:

Projections

Criteria

author: Gavin - King

author: Steve - Ebersole

Method from org.hibernate.criterion.Projection Summary:
getAliases, getColumnAliases, getColumnAliases, getTypes, getTypes, isGrouped, toGroupSqlString, toSqlString

Method from org.hibernate.criterion.Projection Detail:
public String[] getAliases() Get the criteria-level aliases for this projection (ie. the ones that will be passed to the org.hibernate.transform.ResultTransformer )
public String[] getColumnAliases(int position) Get the SQL column aliases used by this projection for the columns it writes for inclusion into the `SELECT` clause (#toSqlString . Hibernate always uses column aliases to extract data from the JDBC java.sql.ResultSet , so it is important that these be implemented correctly in order for Hibernate to be able to extract these val;ues correctly.
public String[] getColumnAliases(String alias, int position) Get the SQL column aliases used by this projection for the columns it writes for inclusion into the `SELECT` clause (#toSqlString for a particular criteria-level alias.
public Type[] getTypes(Criteria criteria, CriteriaQuery criteriaQuery) throws HibernateException Types returned by the rendered SQL fragment . In other words what are the types that would represent the values this projection asked to be pulled into the result set?
public Type[] getTypes(String alias, Criteria criteria, CriteriaQuery criteriaQuery) throws HibernateException Get the return types for a particular user-visible alias. Differs from #getTypes(org.hibernate.Criteria, CriteriaQuery) in that here we are only interested in the types related to the given criteria-level alias.
public boolean isGrouped() Is this projection fragment (`SELECT` clause) also part of the `GROUP BY`
public String toGroupSqlString(Criteria criteria, CriteriaQuery criteriaQuery) throws HibernateException Render the SQL fragment to be used in the `GROUP BY` clause
public String toSqlString(Criteria criteria, int position, CriteriaQuery criteriaQuery) throws HibernateException Render the SQL fragment to be used in the `SELECT` clause.