Results for “ahl_task_links”

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Overview

AHL_TASK_LINKS is a transactional table in the AHL (Complex Maintenance Repair and Overhaul) product family of Oracle E-Business Suite, valid in both 12.1.1 and 12.2.2. It stores the dependency and sequencing relationships that exist between individual tasks belonging to visit tasks in a maintenance, repair, or overhaul work scope. Each row represents one link between a parent task and a subordinate visit task, capturing the precedence constraint and the minimum and maximum separation that must be observed between the two.

From a dimensional modeling perspective, the FK topology mined from the schema suggests this object is best treated as a link table. It resolves a many-to-many relationship between visit task records and carries its own descriptive measures (separation intervals and precedence rules), which is the classic role of a link in a Data Vault model. It is not a hub, because the primary key is a generated surrogate rather than a natural business key, and it is not a pure satellite, because it introduces associations between other entities.

Key Information Stored

The table contains 31 documented columns. The most significant are:

• TASK_LINK_ID — the surrogate primary key, enforced by the AHL_TASK_LINKS_PK constraint and mirrored by the unique index AHL_TASK_LINKS_U1. This is the column most often referenced when users search for ahl_task_links_pk.
• VISIT_TASK_ID — foreign key to AHL_VISIT_TASKS_B, identifying the child or dependent task in the link.
• PARENT_TASK_ID — foreign key to AHL_VISIT_TASKS_B, identifying the predecessor or governing task.
• PRECEDENCE_CONSTRAINT — encodes the ordering rule that governs how the child task may be scheduled relative to the parent.
• MIN_SEPARATION and MIN_SEP_TIME_UNIT — the minimum elapsed interval and its unit of measure allowed between the two tasks.
• MAX_SEPARATION and MAX_SEP_TIME_UNIT — the maximum elapsed interval and its unit of measure allowed between the two tasks.
• SECURITY_GROUP_ID — foreign key to FND_SECURITY_GROUPS, driving multi-org style data access filtering.
• OBJECT_VERSION_NUMBER — optimistic locking column used by the OAF framework.
• CREATED_BY, CREATION_DATE, LAST_UPDATED_BY, LAST_UPDATE_DATE, LAST_UPDATE_LOGIN — standard WHO audit columns.
• ATTRIBUTE_CATEGORY and ATTRIBUTE1 through ATTRIBUTE15 — the standard DFF (descriptive flexfield) storage used for customer-specific extensions.

The unique index AHL_TASK_LINKS_U1 on TASK_LINK_ID is technically a redundant surrogate key index rather than a true business-key candidate; the real business uniqueness is implied by the combination of VISIT_TASK_ID and PARENT_TASK_ID.

Common Use Cases and Queries

Typical queries resolve the task network for a given visit task, determine scheduling constraints, or report on maintenance dependencies.

• Retrieve all children of a task:

  SELECT TASK_LINK_ID, VISIT_TASK_ID, PRECEDENCE_CONSTRAINT,
         MIN_SEPARATION, MIN_SEP_TIME_UNIT,
         MAX_SEPARATION, MAX_SEP_TIME_UNIT
  FROM   AHL.AHL_TASK_LINKS
  WHERE  PARENT_TASK_ID = :p_parent_task_id;

• Join to AHL_VISIT_TASKS_B twice to resolve both ends of the link:

  SELECT p.TASK_ID parent_task, c.TASK_ID child_task, l.PRECEDENCE_CONSTRAINT
  FROM   AHL.AHL_TASK_LINKS l,
         AHL.AHL_VISIT_TASKS_B p,
         AHL.AHL_VISIT_TASKS_B c
  WHERE  l.PARENT_TASK_ID = p.TASK_ID
  AND    l.VISIT_TASK_ID  = c.TASK_ID;

• Locate a specific link by its primary key:

  SELECT * FROM AHL.AHL_TASK_LINKS WHERE TASK_LINK_ID = :p_task_link_id;

• Security-filtered reporting by joining to FND_SECURITY_GROUPS on SECURITY_GROUP_ID.
• DFF-driven reporting using ATTRIBUTE_CATEGORY and the ATTRIBUTE columns.

Related Objects

• AHL_VISIT_TASKS_B — referenced twice, via VISIT_TASK_ID and PARENT_TASK_ID; the primary join target.
• AHL_VISIT_TASKS_TL — typically joined for translated task names.
• FND_SECURITY_GROUPS — referenced via SECURITY_GROUP_ID for access control.
• AHL_TASK_LINKS_PK / AHL_TASK_LINKS_U1 — primary key constraint and unique index on TASK_LINK_ID.
• AHL_WORK_ORDERS / AHL_VISITS — parent entities that ultimately drive visit task creation.
• FND_FLEX_VALUES / FND_DESCR_FLEX_COL_USAGE — descriptive flexfield metadata backing the ATTRIBUTE columns.