Database and object structure of ObjectARX AutoCAD

I. symbol table

A cad drawing is a database containing multiple tables. It specifies nine symbol tables (see the table below). You cannot add new symbol tables.

Symbol table name	Symbol table function
Acdbviewtable (View charts)	Applicable to the acdbviewtablerecord class, indicating the views stored in the database. View is associated with the "View" command of CAD
Acdbviewporttable)	Applicable to the acdbviewporttablerecord class, which indicates the view setting when the tilemode value of the current system variable in CAD is 1. The view configuration is created by the CAD vports command. Do not confuse it with the mview command. When the system variable tilemode value is 0, this command creates a viewport object.
Acdblinetypetable (Linear table)	Applicable to the acdblinetypetablerecord class, indicating the linearity in the graph database.
Acdblayertable (Layer table)	ApplicableAcdblayertablerecord class, indicating layers.
Acdbtextstyletable (Text style sheet)	Applies to the acdbtextstyletable class, indicating the text style.
Acdbucstable (User coordinate system table)	Applicable to the acdbucstablerecord class, indicating the user coordinate system stored in the graphic database.
Acdbregapptable (ApplicationProgramRegistry name)	Applicable to the acdbregapptablerecord class, which represents the application name registered for the extended object data of objects in the graphic database.
Acdbdimstyletable (Dimension and style sheets)	Applies to the acdbdimstyletablerecord class, indicating the dimension style in the graphic database.
Acdbblocktable (Block table)	Applicable to the acdbdimstyletablerecord class, which indicates the block defined in the graphic database. This table contains two important records: model space and drawing space. All entities (visible objects) are protected against block table acdbblocktable.

Summarize the steps required to put entities into a CAD Database. As follows:

1. Create a new object.
2. Open a block table in Read mode.
3. Open the block table record in write mode, and search for acdb_model_space or acdb_paper_space or a layout.
4. Disable block tables.
5. Add an object to a block table record.
6. Disable block table records.
7. Close object.