DT416 Relationship

DI000277 Index

• The index is the identification of the primary key of a data table. Each data table belongs to exactly one index.
  • Example: Data table = 461 Project: Index 461
• The 1:1 relationship of a DT is the basis for the name.
• Example for naming indexes:
  • DT461 Project
  • Index: 461
  • Variable name: ID461

Note

• All foreign key and primary key constraints on the database must also be stored in the Data Dictionary.

DI000278 Ident of DI

Relationships go from an ID no. in a data table to an index. This ID number can be formed from one or more data items. The entry here is the first DI which forms part of the ID no.

Notes

• For type = 2 relationships: DI of the node-ident. The sequence is based on the "DBPos" from the data item.
• Relations are only supported if they are of the same data type.

See also: Ident up to DI

DI000363 Ident up to DI

Last data item which is part of the ID no. for the relationship.

Notes

• For type = 2 relationships: DI to of the knot ID.
• Relations are only supported if they are of the same data type.

See also: Ident from DI

DI000279 Relationship

The relationship for a set is specified as the frequency of occurrence in the data table for any index:

Values

• 1:1 = In the data table, an ID number equal to the index may appear only once
• N:1 = In the data table, an ID number which is equal to this index may appear in an arbitrary number of records.

DI000951 Variable Name

Contains the name of the ID in the database syntax

Examples

• DT463 "Task" has a N:1 relationship to DT461 "Project".
  • The data item in data table 463 is called "ID461".
  • In the relationship the variable name is = "ID461".
• DT465 "Link" has two N:1 relationships to DT463 "Task".
  • As a result, there are two items in data table 465: "ID463A" and "ID463B".
  • The first relationship has the variable name = "ID463A", the second has the variable name = "ID463B".

DI000281 Deletion flag

The delete flag determines the behavior when records are deleted that have a link to records in other data tables.

• In the data table which has the same ID no. as the index for the relationship under consideration, one record will be deleted (referred to below as the current record). What happens to records linked to it which are in the data table to which this relationship belongs?

Values

• 0: Linked records are deleted without asking for confirmation.
• 1: Query, and if appropriate delete the linked records after the user gives positive confirmation. If the user answers the query with No, the linked records will not be deleted, and the current record will also not be deleted.
• 2: The dependent records may not be deleted. This means that the current record itself also cannot be deleted.
• 3: The relationship will be ignored when deleting. The current record will always be deleted, even if the relation concerned means that it has dependent records.

Example

• Data table = 461 Project
  • Relationship: Index = 463, Deletion Flag = 2
• Result:
  • If there is a project in DT461 Project which is to be deleted, and there are associated tasks in DT463 Task, these tasks may not be deleted at the same time. As a result, the project itself also cannot be deleted.

Notes

• Delete flag = 3 may only be used for relationships which do not have to be satisfied. Otherwise, data arises which is application-logically invalid.
• Used mainly for relationships between different databases when a deletion cannot or may not be performed in the other database at the same time.

DI000379 Create implicitly

Determines the behavior of the software in the event that a parent record, required by a relationship, is not present

Values

• 0: An error message is displayed if the parent record does not exist.
• 1: If the parent record does not exist, it is created.
• 2: The record is created implicitly, the error message is suppressed.
• 3: The relationship is ignored during creation, and no dependent record is created if it is not already present.

DI001978 Recursion ID from

Recursion ID from

First data item which is an element in the ID of the successor node. Is only used for Rel. Type = 2.

DI001979 Recursion ID to

Recursion ID to

Last data item which is an element in the ID of the successor node. Is only used for Rel. Type = 2.

DI000374 Relationship type

Relationship type

Values

• 0: is considered quantity relation by PLANTA
• 1: remains disregarded in PPMs when determining the internal module logic
• 2: Recursion relationships

Example

• Disregarded relationship:
  • Task link: the second relationship (to the predecessors) has Relationship type = 1
• Recursion relationships:
  • Module with at least 2 areas:
    • a node area (area 1): the data (records) in this area are to have a structured representation.
    • a linkage area (area 2): the data (records) in this area contain the structure information
  • Example:
    • Area 1: Procedure; they are to be displayed in the network as node
    • Area 2: Link; these say what successors the parent task (node) has
    • It must be possible to find the records in area 2 by means of a normal database relationship.

Information in the Data Dictionary

• The following is described in the data dictionary:
  • a) The path from a node to the linking object
  • b) The path from the linking object to the next or lower node
  • This is effected by 2 recursion relationships.
• These specify
  • for a) (in the first recursion relationship):
    • 1: DI(s) that form the ID of the knot (Ident from DI, Ident to DI)
    • 2: DI(s) in which the ID of the knot is created in the linked object ( Recursion ID from, Recursion ID to)
  • for b) (in the second recursion relationship):
    • 1: DI(s) that form the ident of the next or subordinate node (Recursion ID from, Recursion ID to)
    • 2: DI(s) which form the ID no. of this node in the linking object ( Ident from DI, Ident to DI)
• In the example,
  • a1: is the task ID in the task
  • a2: is the ID of the task’s predecessor in the link
  • b1: is the task ID in the task
  • b2: is the ID of the task’s successor in the link

Information in module area assignment

• Res. Parent area

Information in the area

• DIs of the class 8 for information on the required link type.