Get table name by FieldAlias

[sca...@live.com]

Is it possible to get the table name from a field constructed as the following?

field( name( "MyTable", "myField" ) ).as( "myAlias" )

When I try to get it through .getQualifiedName() it returns only the alias part, without a table name.

[Lukas Eder]

Hello,

There currently isn't such a public API. There's a pending feature request to help discover such things:

https://github.com/jOOQ/jOOQ/issues/2579

But I'm currently not sure if opening up such API is a good idea - it's hard to keep the internal QueryPart APIs backwards compatible. Also, an aliased field is quite a different thing from the original field reference. For one, it can alias anything, including expressions based on several field references and other expressions, such as:

first_name || ' ' || last_name AS name

Of course, you can keep a reference to your unaliased field and fetch the qualified name from that:

Field<?> original = field( name( "MyTable", "myField" ) );

Field<?> aliased = original.as( "myAlias" );

String tableName = original.getQualifiedName().qualifier().last();

But I suspect the logic creating the alias is disconnected from the logic referencing it.

As another workaround, you can use reflection on jOOQ's internals.

A third workaround would be to traverse the expression tree using a VisitListener and introspect the individual parts being traversed...

I hope this helps,
Lukas

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[sca...@live.com]

Hi Lukas,

Thank you for your answer, I get it now why an alias sometimes shouldn't have a reference to a table: even considering that some expression like "'myvar' as myvar" is in context of some table, it is not really related to the table by its nature.

I think I'll go with keeping a reference to the original field - it is already kind of what I'm already doing.

Also it's nice to see that a lot of cases already have corresponding issues on GitHub :)

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[Lukas Eder]

Also it's nice to see that a lot of cases already have corresponding issues on GitHub :)

Oh yeah - jOOQ has been around for a while, and so have been the various ideas to enhance it. The question is just: Is there a more generic new feature that would allow for solving dozens of issues at once, rather than solving them individually :)

Cheers,

Lukas