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mirror of synced 2024-12-14 15:16:04 +03:00

FAQ and Composite Key renaming

This commit is contained in:
Benjamin Eberlei 2011-07-13 19:04:21 +02:00
parent c876f9edb2
commit 660ead4b0e
2 changed files with 8 additions and 8 deletions

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@ -172,15 +172,15 @@ What is DQL?
DQL stands for Doctrine Query Language, a query language that very much looks like SQL
but has some important benefits when using Doctrine:
* It uses class names and fields instead of tables and columns, separating concerns between backend and your object model.
* It utilizes the metadata defined to offer a range of shortcuts when writing. For example you do not have to specify the ON clause of joins, since Doctrine already knows about them.
* It adds some functionality that is related to object management and transforms them into SQL.
- It uses class names and fields instead of tables and columns, separating concerns between backend and your object model.
- It utilizes the metadata defined to offer a range of shortcuts when writing. For example you do not have to specify the ON clause of joins, since Doctrine already knows about them.
- It adds some functionality that is related to object management and transforms them into SQL.
It also has some drawbacks of course:
* The syntax is slightly different to SQL so you have to learn and remember the differences.
* To be vendor independent it can only implement a subset of all the existing SQL dialects. Vendor specific functionality and optimizations cannot be used through DQL unless implemented by you explicitly.
* For some DQL constructs subselects are used which are known to be slow in MySQL.
- The syntax is slightly different to SQL so you have to learn and remember the differences.
- To be vendor independent it can only implement a subset of all the existing SQL dialects. Vendor specific functionality and optimizations cannot be used through DQL unless implemented by you explicitly.
- For some DQL constructs subselects are used which are known to be slow in MySQL.
Can I sort by a function (for example ORDER BY RAND()) in DQL?
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@ -1,5 +1,5 @@
Composite Primary Keys
======================
Composite and Foreign Keys as Primary Key
=========================================
Doctrine 2 supports composite primary keys natively. Composite keys are a very powerful relational database concept
and we took good care to make sure Doctrine 2 supports as many of the composite primary key use-cases.