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KJoinDefinition

Definition​

A KJoinDefinition object contain all necessary information to join two tables in a query.

This object can only be built through the on method available on KTable objects and KCommonTableExpressionFilled objects:

Available on methods​

1. on(KCondition kCondition)​

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

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

2. on(KRaw kRaw)​

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

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

Those KTable that are automatically generated bring with them additional predefined methods that return a KJoinDefinition according to the relationships between tables that are detected in the database diagram.

The syntax of these additional methods is:

join + TableNameUpperCamelCase

Learn how to generate KTable automatically.

tip

The KTable that calls the on method will be the one that will be introduced in the join.

Example: KCondition​

Java code:

k
.select(
    APP_USER.FIRST_NAME,
    ROLE.TENANT_ID
)
.from(APP_USER)
.innerJoin(ROLE.on(APP_USER.ROLE_ID.eq(ROLE.ID)))
.multiple();

SQL generated:

SELECT au.first_name, ro.tenant_id
FROM app_user au
INNER JOIN role ro ON (au.role_id = ro.id)

Parameters:

  • None

Example: KRaw​

Java code:

k
.select(
    APP_USER.FIRST_NAME,
    ROLE.TENANT_ID
)
.from(APP_USER)
.innerJoin(ROLE.on(raw("au.role_id = ro.id")))
.multiple();

SQL generated:

SELECT au.first_name, ro.tenant_id
FROM app_user au
INNER JOIN role ro ON (au.role_id = ro.id)

Parameters:

  • None

Example: Predefined method​

Java code:

k
.select(
    APP_USER.FIRST_NAME,
    ROLE.TENANT_ID
)
.from(APP_USER)
.innerJoin(APP_USER.joinRole())
.multiple();

SQL generated:

SELECT au.first_name, ro.tenant_id
FROM app_user au
INNER JOIN role ro ON (au.role_id = ro.id)

Parameters:

  • None