Teigha Mechanical: Bill Of Materials Physical Data Model in OdDbDatabase

Andrii Morozov
October 31, 2017

Tags: mechanical getting started

Bill Of Materials is a table that holds all parts and components with corresponding data and attributes. The logical representation is quite easy to understand but the physical data model of a BOM table is a complex concept that includes components, parts and data containers.

Mechanical dictionary

All common data that relates to Teigha Mechanical is located in a couple of dictionaries, particularly AcmDictionary.

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AcmDictionary in the database

AcmDictionary holds data related to Bill Of Materials: AcmBOM dictionary and AcmDataDictionary. Also the dictionary holds some common data such as the standards dictionary.

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BOM dictionary

Mechanical data dictionary

Another important dictionary is the AcmBOMDATA dictionary. This dictionary relates to AcmDataDictionary. Basically, AcmBOMDATA holds data containers for BOM rows and BOM tables.

A data container can be any of the following types: DataEntry, DataEntryPart, or DataEntryBlock. The AcmDataDictionary class handles and works with BOM Data:

OdResult  append(AcmDataEntryPtr pDataEntry, OdDbObjectId& newObjId);
OdResult createDataEntryFor(AcmBomPtr& pBom, const OdDbObjectId& targetId, OdDbObjectId& objId);
OdResult  createDataEntryFor2DCompDef(const OdDbObjectId& targetId, OdDbObjectId& objId);
OdResult  createDataEntryFor(const OdDbBlockTableRecordPtr& pBlockTableRecord, OdDbObjectId& objId);
OdResult getDataEntryByCompDefId(const OdDbObjectId& compDefId, OdDbObjectId& dataEntryId) const;
  • append(AcmDataEntryPtr pDataEntry, OdDbObjectId& newObjId) — Adds a new data entry container to an existing dictionary.
  • createDataEntryFor() — This group of methods creates new data entry containers.
  • getDataEntryByCompDefId(const OdDbObjectId& compDefId, OdDbObjectId& dataEntryId) — Returns the data entry container for a component definition object.
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BOMData dictionary and DataEntries

DbInfo service class

AcadmDbInfo is a service class that works with AcmDataDictionary. This service class is designed to make working with Teigha Mechanical dictionaries easier.

OdDbObjectId acmDictionaryId();
OdDbObjectId bomDictionaryId();
OdDbObjectId dataDictionaryId();
OdDbObjectId createBomDictionary();
  • acmDictionaryId() — Returns the AcmDictionary OdDbObjectId for the current database.
  • bomDictionaryId() — Returns the AcmBOM OdDbObjectId for the current database.
  • dataDictionaryId() — Returns the AcmBOMDATA OdDbObjectId for the current database.
  • createBomDictionary() — Creates a new AcmBOM dictionary for the current database if it's missing.

BOM objects

The AcmBom class represents a Bill Of Materials table object. An AcmBom object holds a data entry container with appropriate data for the BOM table and BOM rows that represent BOM items.

OdString                          name() const;
OdDbHardPointerId                 dataEntryId() const;
void                              setDataEntryId(OdDbHardPointerId objId);
void                              setName(OdString name);
bool                              isExpandedBOM() const;
OdInt16                           itemNumberStep() const;
OdString                          itemNumberStart() const;
void                              setItemNumberStart(const OdString& itemNumberStart);
void                              setItemNumberStep(OdInt16 itemNumberStep);
  • dataEntryId() — Returns the BOM table data container.
  • setDataEntryId(OdDbHardPointerId objId) — Sets a data container for the BOM table.
  • name() — Returns the name of the BOM table.
  • setName(OdString name) — Sets a name for the BOM table.
  • isExpandedBOM() — Returns true if the BOM is expanded, false if structured.
  • itemNumberStep() — Returns the number step of the item attribute for the BOM table.
  • itemNumberStart() — Returns the first number of the attribute for the BOM table.
  • setItemNumberStart(const OdString& itemNumberStart) — Sets an item number step for the BOM table.
  • setItemNumberStep(OdInt16 itemNumberStep) — Sets the first number for the BOM table.

BOM rows

The AcmBomRow class represents a BOM table item. BomRow also holds a data container.

OdString                 getItemName() const;
OdDbHardPointerId        getDataEntryId() const;
virtual bool             isVisible() const;
bool                     isToExpand() const;
OdInt32                  getSortPriority();
void                     setSortPriority(OdInt32 priority);
  • getItemName() — Returns the item name.
  • getDataEntryId() — Returns the data container.
  • isVisible() — Returns true if the item is visible.
  • isToExpand() — Returns true if the item in an expanded BOM.
  • getSortPriority() — Returns the sort priority.
  • setSortPriority(OdInt32 priority) — Sets the sort priority for the item.
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BomRow and Bom

Conclusion

A Bill Of Materials is a set of dictionaries that has a subset of BOM items (rows) and data containers (data entries). Rows and entries are connected to each other, and rows are connected to components.

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