You can maintain database storage parameters for PSA tables, master data tables, InfoCube fact- and dimension tables, and ODS tables.
Use this setting to determine how the system handles the table when it creates it in the database:
Use Data Type to set in which physical database area (tablespace) the system is to create the table. Each data type (master data, transaction data, organization- and Customizing data, customer data) has its own physical database area, in which all tables assigned to this data type are stored. If selected correctly, your table is automatically assigned to the correct area when it is created in the database. We recommend you use separate tablespaces for very large tables.
You can find information about creating a new data type in SAPNet R/3 Frontend in note 0046272 (Introduce new data type in technical settings).
Via Size Category, you can set the amount of space the table is thought to need in the database. Five categories are available in the input help. You can also see here how many data records correspond to each individual category. When creating the table, the system reserves an initial storage space in the database. If the table later requires more storage space, it obtains it as set out in the size category. Correctly setting the size category prevents there being too many small extents (save areas) for a table. It also prevents the wastage of storage space when creating extents that are too large. You can use the maintenance for storage parameters to better manage databases that support this concept.
You can find additional information about the data type and size category parameters in the ABAP Dictionary table documentation, under Technical Settings.