Why do I need to configure the SQL dialect of a data source?

Question

When we configure a data source using Hibernate, we should add the hibernate.dialect property (or eclipselink.target-database if you are using Ecli

Answer 1

Hibernate uses "dialect" configuration to know which database you are using so that it can convert hibernate query to database specific query.

Answer 2

Dialect property is used by hibernate in following ways

1. To generate Optimized SQL queries.
2. If you have more than one DB then to talk with particular DB you want.
3. To set default values for hibernate configuration file properties based on the DB software we use even though they are not specifed in configuration file.

Answer 3

Dialect means "the variant of a language". Hibernate, as we know, is database agnostic. It can work with different databases. However, databases have proprietary extensions/native SQL variations, and set/sub-set of SQL standard implementations. Therefore at some point hibernate has to use database specific SQL. Hibernate uses "dialect" configuration to know which database you are using so that it can switch to the database specific SQL generator code wherever/whenever necessary.

Answer 4

Short answer

hibernate.dialect property makes Hibernate to generate the appropriate SQL statements for the chosen database.

Answer 5

The dialect in the Hibernate context, will take care of database data type, like in orace it is integer however in SQL it is int, so this will by known in hibernate by this property, how to map the fields internally.

Answer 6

Databases implement subtle differences in the SQL they use. Things such as data types for example vary across databases (e.g. in Oracle You might put an integer value in a number field and in SQL Server use an int field). Or database specific functionality - selecting the top n rows is different depending on the database. The dialect abstracts this so you don't have to worry about it.