73 lines
3.8 KiB
Plaintext
73 lines
3.8 KiB
Plaintext
= Dialects
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A dialect is a class that provides information about the specifics of a database and translators for the SQL dialect of the database.
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== Supported dialects
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Hibernate supports a wide range of dialects out of the box. The following is list of officially supported databases:
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* Apache Derby
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* Cockroach
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* Google Spanner
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* H2
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* HSQLDB
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* IBM DB2 LUW
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* IBM DB2 iSeries
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* IBM DB2 z/OS
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* MariaDB
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* MySQL
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* Oracle
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* PostgreSQL
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* Postgres Plus
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* SAP HANA
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* SQL Server
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* Sybase ASE
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Usually, Hibernate supports at least the database version that is also still supported by the respective vendor.
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In many cases though, Hibernate supports even older versions of the databases,
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but the support for these versions is not guaranteed.
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Apart from the Hibernate team supported dialects, there are also community dialects.
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== Community dialects
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As of Hibernate 6.0, the Hibernate team decided to provide a clear way forward for community contributed dialects.
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The `hibernate-core` artifact had many legacy dialects before 6.0 that were only tested and maintained on a best effort basis.
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More and more database vendors requested to integrate a dialect for their database and even provided a PR with a dialect,
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but the Hibernate team didn't want to add new dialects for databases that might not have a wide adoption
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or any automated testing into the `hibernate-core` artifact. Even though the dialect was supposedly maintained by the vendor,
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the Hibernate team was burdened with reviewing questions, issues and PRs that relate to these dialects.
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To give database vendors and the community a clear way forward, the Hibernate team decided to introduce a new artifact,
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called `hibernate-community-dialects` which is the new home for dialects that are maintained by vendors or individuals.
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Starting with Hibernate 6.0 the `hibernate-core` artifact will only contain dialects that are supported and tested by the Hibernate team.
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All the legacy dialects are moved to the `hibernate-community-dialects` artifact to have a clear separation based on the quality of the dialect.
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Issues with dialects in the `hibernate-community-dialects` are usually not considered by the Hibernate team,
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as the community is responsible for providing fixes and improving the dialects for newer database versions or ORM capabilities.
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== Requirements for moving to hibernate-core
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If a database vendor wants their database dialect to be included in the `hibernate-core` artifact,
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several requirements have to be fulfilled:
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* The vendor must provide access to a dedicated database server that can be used for testing
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* The vendor must provide contact details to at least one employee who is mainly responsible for the maintenance of the dialect
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* The responsible employee of the vendor must actively monitor and react to failures of the testsuite against the respective database
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* The responsible employee of the vendor must ensure the testsuite is configured correctly in order for it to succeed on the respective database
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* If the responsible employee of the vendor leaves the company, the vendor must provide contact details to a new responsible employee
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In case the responsible employee is unreachable for a longer period or issues with the dialect are not attended to in a timely manner,
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the Hibernate team will move the dialect back to the `hibernate-community-dialects` artifact.
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The requirements for the database server are:
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* JDK 8 installed through e.g. `sudo yum install -y java-1.8.0-openjdk-devel`
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* JDK 11 installed through e.g. `sudo yum install -y java-11-openjdk-devel`
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* Git installed through e.g. `sudo yum install -y git`
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* Access to the database through non-confidential credentials
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* Access via SSH through confidential credentials
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Get in touch with the Hibernate team on https://hibernate.zulipchat.com/#narrow/stream/132096-hibernate-user[Zulip]
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if you want to request the move of your dialect to hibernate-core. |