Joins

Joins: A join object creates a relationship between a business component and table other than its base table.
This relationship allows the business component to use columns from other table.
A join is always 1:1 relationship and it is always between a business component and a table.
Joins are two types.
1. Implicit joins
2. Explicit joins
Implicit joins:
Implicit joins exist as part of the Siebel object architecture. They are not explicitly defined using Siebel tools.
Unlike joins that you define in Siebel tools user can update the columns from implicit joins.
Implicit joins exist for the following
1. All 1:1 (_X) extension tables and all relevant intersection tables.
2. Extension tables of S_PARTY, such as S_ORG_EXT, S_CONTACT, S_POSTN and S_USER.
Explicit joins:
We are explicitly defined using Siebel tools.
When creating a joined field in a BC, you can change the type property from the default DTYPE_TEXT to a more appropriate type. DTYPE_TEXT refers to the data as a string of length 2000 or less
The Type property of a Field object type definition corresponds to the physical type of the column in the underlying table.
For example, if you are joining a table column that contains phone numbers, you can change the type field to DTYPE_PHONE.
Set the “outer join flag” to “TRUE”, if you want to retrieve all the records in the business component even when the joined fields are empty.
 “Join specification” object definition identifies the foreign key field in the business component & the primary key column in the joined table.
 The “Source field property” identifies the foreign key column in the joined table.
 In rare circumstances, there can be multiple join specifications in a single join.
For example, the sub campaign BC has a join to the S_LANG table with two join specifications.
 A “Join constraint” is a constant-valued search specification applied to a column during a join. It is for use with outer join.
 “Foreign key column” represents in the base table, pointing to rows in a particular table used in joins.
 “Join table” provides the columns to the BC through the join. It is a master table.
 The “Primary key column” identifies the joined table. Every standard table in standard Siebel application has a ROW_ID column that uniquely identifies rows in the table.
Mapped Column: Columns in the joined table are available for use in the fields in the BC.
 When bring in party data into a nonparty BC, create a new join with the join specification based on PAR_ROW_ID.
 When bringing in party data into a party BC, use appropriate explicit join.
 When mapping fields in party BC, use the implicit join for the extension table.
 You cannot use a pre-default value in the regular way as a default field value if nothing is specified when a record is inserted.