The database of Mapinfo adopts a hybrid spatial database structure, and different modules are used to store spatial data and attribute data. Attribute data is stored in several attribute tables of relational database, while spatial data is stored in several files in the custom format of Mapinfo, and the two are linked by a certain index mechanism. In order to improve the efficiency of query and processing, Mapinfo uses a hierarchical structure to organize spatial data, that is, the map is layered according to different topics, and each layer is composed of five files.

1.Table structure file of attribute data (.TAB)

It defines the table structure of map attribute data, including the number of fields, field names, field types and field widths, key spatial information descriptions of index fields and corresponding layers. The TAB file is actually a text file.

2. Attribute data file (.DAT)

It is used to store complete map attribute data， it includes file header, table structure description, and each attribute data record.

3. Cross-index file (.ID)

It records the location pointer of each spatial object in the spatial data file in the map. The order of the columns of the pointer is the same as the order in which the attribute data records are stored in the property data file. It is actually a positioning table of spatial objects.

4. Spatial data file (.map)

It contains the spatial properties of each map object. For example, the geometric type, coordinate information and color information of the object. The record number recorded in the attribute data file with the attribute data of the spatial object is also described. when the user queries a certain map object from the map, the related attribute information can be found.

5. Index file (.Ind)

It is not necessary, and the system will generate it automatically only when the user specifies the index field of the database.