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Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for the ‘Spring4D’ Category

Spring4d Marshmallow ORM – ensuring the right identifier quoting is used

Posted by jpluimers on 2019/10/29

When an ORM generates the SQL for a certain database back-end, it needs to use the right quoting.

Normally, the Spring4D Marshmallow project derives that from the back-end specific adapter used.

But if you use a generic TDriverConnectionAdapter, then you need to manually set the QueryLanguage property in your IDBConnection using a valid value from Spring.Persistence.SQL.Interfaces. This then uses the correct SQLGenerator from the TSQLGeneratorRegister to generate the SQL including correct quotes.

To quote identifiers, most back-ends use a double quote, but MySQL uses a backtick.

via:

You obviously already modified that code as the commented out code is the correct one.
I guess you already got that mistake when you started using MySQL via ADO as MySQL needs the backtick.

Set QueryLanguage of your IDBConnection properly (the valid values are in Spring.Persistence.SQL.Interfaces). Then the correct SQLGenerator will be used.
If you are using an adapter that is specific to a certain database then it sets the QueryLanguage properly but if you are using an adapter for components that can connect to multiple databases (like ADO or FireDAC) it does not, hence the need you specify it.

 

–jeroen

Posted in Delphi, Development, Software Development, Spring4D | Leave a Comment »

Spring4D and factory – for my link archive

Posted by jpluimers on 2019/10/23

So I remember as resolving container things can be tricky:

–jeroen

Posted in Delphi, Development, Software Development, Spring4D | Leave a Comment »

does anyone know of any Spring.Container examples (preferably non trivial) th…

Posted by jpluimers on 2019/09/26

Via [WayBack] does anyone know of any Spring.Container examples (preferably non trivial) that show how to build an app with a container just referenced from the Compo… – Russell Weetch – Google+:

Stefan Glienke:

The principle of having a composition root has nothing to do with a particular DI container. Its what you eventually get when following the principle if DI: ask for dependencies – don’t create or look for them yourself (aka service locator).

You did not mention it but I guess you mean a VCL application – now the design of the VCL is not particularly built with DI in mind and thus it can be a bit tricky to hook up the application MainForm to the container to get it injected everything. However there are several examples how to achieve that (mainly by using DelegateTo and doing the Application.CreateForm there).

An example explaining this is for instance in [WayBack] How to initialize main application form in Spring4D GlobalContainer?

Many more can be found through Spring4d DelegateTo and Spring4d DelegateTo CreateForm and

–jeroen

Posted in Delphi, Development, Software Development, Spring4D | Leave a Comment »

Interface methods are not assignment compatible with method references or methods of object.

Posted by jpluimers on 2019/04/02

Boy I wish that QC was still up and QualityPortal was publicly indexable as that would have saved me quite a bit of time tracking this down. Luckily I got help from Stefan Glienke (who maintains the awesome Spring4D library based on modern Delphi compiler support) when I mentioned

How good are you with reference to function?
I’ve an odd compiler thing throwing errors when using interfaces but not with classes.

So, for posterity:

Unlike C#, in Delphi interface methods are not compatible with method references or methods of object.

This has many manifestations, which means you can get a variety of compiler errors. I’ve listed the ones I could find below, but presume there are more and if I find more will update this post.

These are the errors you can get:

  • E2010 Incompatible types: ‘T’ and ‘Procedure’
  • E2035 Not enough actual parameters
  • E2250 There is no overloaded version of ‘FirstOrDefault’ that can be called with these arguments

These are the (now defunct, but used to be publicly accessible) QC and QualityPortal (needs sign on) entries (thanks Stefan Glienke and Blaise Thorn for reporting these):

The really frustrating part is that the RSP is marked as “new feature” whereas clearly it isn’t, so it probably never will be fixed.

A workaround for now is to wrap the interface method references with:

  • either anonymous methods (when you have just a few classes to cover, but maybe more than a few methods on the interface)
  • or instance methods on a class (when there are many classes to cover and preferably few methods on the interface)

Examples are in the code below that also shows this works fine and dandy in C#.

–jeroen

Read the rest of this entry »

Posted in Delphi, Delphi 10 Seattle, Delphi 10.1 Berlin (BigBen), Delphi 10.2 Tokyo (Godzilla), Delphi XE3, Delphi XE4, Delphi XE5, Delphi XE6, Delphi XE7, Delphi XE8, Development, Software Development, Spring4D | Leave a Comment »

When I ever go and use the Spring4D activator, these are some URLs I need to re-read

Posted by jpluimers on 2019/03/27

When I ever go and use the Spring4D activator, these are some URLs I need to re-read:

–jeroen

Posted in Delphi, Development, Software Development, Spring4D | Leave a Comment »

 
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