QBJoin

Overview

The QBJoin class simplifies the process of creating and managing SQL joins within the QBSelect query builder framework. It provides tools to handle complex relationships between tables, enabling construction of queries with various join types, such as LEFT OUTER JOIN or INNER JOIN. By leveraging the class, developers can define join conditions and access columns from related tables for select or where clauses.

The class supports dynamic query building with its integration of parent and root query references, ensuring flexibility and scalability in query design. It also allows for annotating joins with comments, aiding in query documentation and readability.

For further details on constructing and executing queries, refer to the QBSelect documentation.

Properties Summarized

Type	Name	Summary
QBColumns	columns	Get all the columns of the datasource that can be used for this query (select or where clause)
String	comment	Specifies a comment of the join.
Number	joinType	Returns the join type, one of IQueryBuilderJoin#LEFT_OUTER_JOIN, IQueryBuilderJoin#INNER_JOIN, IQueryBuilderJoin#RIGHT_OUTER_JOIN, IQueryBuilderJoin#FULL_JOIN
QBJoins	joins	Get the joins clause of this table based clause.
QBLogicalCondition	on	Get the on clause for the join.
QBTableClause	parent	Get query builder parent table clause, this may be a query or a join clause.
QBSelect	root	Get query builder parent.

Methods Summarized

Type	Name	Summary
QBColumn	getColumn(name)	Get a column from the table.
QBColumn	getColumn(columnTableAlias, name)	Get a column from the table with given alias.
String	getDataSource()	Returns the datasource for this.
String	getTableAlias()	Returns the table alias for this.

Properties Detailed

columns

Get all the columns of the datasource that can be used for this query (select or where clause)

Type QBColumns

Sample

var query = foundset.getQuery();
query.result.add(query.columns.name, "name");
query.where.add(query.columns.orderdate.isNull)

comment

Specifies a comment of the join.

Type String

Sample

var query = datasources.db.example_data.orders.createSelect();
query.result.add(query.joins.orders_to_orderlines.columns.price)
query.joins.orders_to_orderlines.comment = 'Join comment'

joinType

Returns the join type, one of IQueryBuilderJoin#LEFT_OUTER_JOIN, IQueryBuilderJoin#INNER_JOIN, IQueryBuilderJoin#RIGHT_OUTER_JOIN, IQueryBuilderJoin#FULL_JOIN

Type Number joinType.

joins

Get the joins clause of this table based clause. Joins added to this clause will be based on this table clauses table.

Type QBJoins

Sample

foundset.getQuery().joins

on

Get the on clause for the join.

Type QBLogicalCondition

Sample

var query = datasources.db.example_data.person.createSelect();
/** @type {QBJoin<db:/example_data/person>} */
var join1 = query.joins.add('db:/example_data/person')
join1.on.add(query.columns.parent_person_id.eq(join1.columns.person_id))
/** @type {QBJoin<db:/example_data/person>} */
var join2 = query.joins.add('db:/example_data/person')
join2.on.add(join1.columns.parent_person_id.eq(join2.columns.person_id))

query.where.add(join2.columns.name.eq('john'))
foundset.loadRecords(query)

parent

Get query builder parent table clause, this may be a query or a join clause.

Type QBTableClause

Sample

var query = datasources.db.example_data.person.createSelect();
	query.where.add(query.joins.person_to_parent.joins.person_to_parent.columns.name.eq('john'))
	foundset.loadRecords(query)

root

Get query builder parent.

Type QBSelect

Sample

var subquery = datasources.db.example_data.order_details.createSelect();

	var query = datasources.db.example_data.orders.createSelect();
	query.where.add(query
		.or
			.add(query.columns.order_id.not.isin([1, 2, 3]))

			.add(query.exists(
					subquery.where.add(subquery.columns.orderid.eq(query.columns.order_id)).root
			))
		)

	foundset.loadRecords(query)

Methods Detailed

getColumn(name)

Get a column from the table.

Parameters

• String name the name of column to get

Returns: QBColumn

Sample

foundset.getQuery().getColumn('orderid')

getColumn(columnTableAlias, name)

Get a column from the table with given alias. The alias may be of the main table or any level deep joined table.

Parameters

• String columnTableAlias the alias for the table

• String name the name of column to get

Returns: QBColumn

Sample

foundset.getQuery().getColumn('orderid', 'opk')

getDataSource()

Returns the datasource for this.

Returns: String the dataSource

getTableAlias()

Returns the table alias for this.

Returns: String the tableAlias

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