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KTable

Definition​

A KTable object references a database table.

KTable types​

There are 2 types of KTable:

  • Generated: Those that are generated automatically and found in the generated.metadata package, which refer directly to a table in the database. Learn how to generate KTable automatically.
  • Subquery: Those that are built from a subquery. These do not reference a table in the database.

Build a KTable from a subquery​

To get started building a KTable from a subquery, you need to prepare a KQuery and then through the as method you supply an alias and so the KQuery becomes a KTable, as follows:

final KTable kTable =
    k
    .select(APP_USER.ID)
    .from(APP_USER)
    .as("an_alias");

Methods available in a KTable​

1. column(String name)​

Allow you to generate a new KColumn that can be used in any other clause. This KColumn has the peculiarity that it already includes the KTable alias.

  • name: is the name of the column to generate.

2. c(String name)​

This method does the same as method column but with a shorter name.

3. on(KCondition kCondition)​

This method allows the KTable to be added to a JOIN clause.

  • kCondition: which contains all the information about the condition that will be supplied to the JOIN clause.

4. on(KRaw kRaw)​

This method allows the KTable to be added to JOIN clause.

  • kRaw: is a raw content which will be supplied in the JOIN clause.
tip

The c and column methods are only really useful in those KTable that are built from a subquery.