What is HQL in Hibernate with example?
Hibernate Query Language (HQL) is an object-oriented query language, similar to SQL, but instead of operating on tables and columns, HQL works with persistent objects and their properties. HQL queries are translated by Hibernate into conventional SQL queries, which in turns perform action on database.
Why do we use HQL?
HQL helps in writing database independent queries that are converted into the native SQL syntax of the database at runtime. This approach helps to use the additional features that the native SQL query provides.
How do I join Hibernate?
We can apply the Joins in Hibernate by using the HQL query or native SQL query. To make a join between the two tables, the two tables must be in a logical relationship. We can achieve the relationship between two tables by applying the parent table’s primary key as a child table’s foreign key.
How Hibernate handles join?
Following is a step by step guide to show hibernate join statement.
- 4.1 Create a Maven project. Create a new maven project in eclipse.
- 4.2 Add Hibernate Dependencies.
- 4.3 Create Hibernate Configuration File.
- 4.4 Create entities.
- 4.5 Map Java objects to database.
- 4.6 Hibernate Test Program.
How do I write a query in hive?
SELECT – The SELECT statement in Hive functions similarly to the SELECT statement in SQL. It is primarily for retrieving data from the database. INSERT – The INSERT clause loads the data into a Hive table. Users can also perform an insert to both the Hive table and/or partition.
Where is HQL used?
An HQL SELECT is used to query the database for classes and their properties. The fully qualified name of an entity is path . The alias names may be used to abbreviate references to specific entities or their properties and must be used when property names used in the query would otherwise be ambiguous.
Which is better HQL or SQL?
Traditional SQL code is longer than the HQL code. SQL is usually faster than the non-native HQL, however, by setting the correct cache size of the query plan, HQL can be made to operate as fast as SQL.
How do I join a table in HQL?
Related
- HQL query to join 2 tables with the same key.
- select in Nhibernate by HQL.
- HQL left join of un-related entities.
- HQL query with two joins expressed in Criteria API.
- Inner join using HQL.
- NamedQuery and inner join associaton.
- HQL Join – Path expected for join!
- HQL equivalent for additional conditions in LEFT JOIN.
How do I write a left join in HQL?
select * from A as a left join B as b on a.id = b.id left join C as c on b. type=c.