Estimating Database Size

You can estimate the size of a database for all or a selection of tables in the model.

You obtain an estimate based on the following elements:


  • Estimated number of records in tables - Specify the number of records in a table in the Number field on the General tab of its property sheet (see Table Properties).

    To specify this value for multiple tables, use the List of Tables (Model > Tables. If you do not see the Number column, then add it using the Customize Columns and Filter tool.

  • Table columns and their sizes - Specify the average size for a column with a variable length data type in the Average length field on the Detail tab of its property sheet (see Column Properties).

    To specify this value for multiple columns, use the List of Columns (Model > Columns. If you do not see the Average length column, then add it using the Customize Columns and Filter tool.

    Note:

    If you do not specify an average length for variable length columns, then the maximum length is used. It is particularly important to specify an average length for strings or long binary data types, as a Binary Long OBject (BLOB), such as a picture, can represent the largest portion of the space actually taken by a table.

  • Indexes in the model - including primary, alternate, and foreign key indexes (if supported) and database-specific indexes such as IQ join indexes.

  • Tablespaces in the model - the size of a tablespace is estimated as a total of all the tables and all the indexes in the tablespace.

  • DBMS and its storage options

  1. Select Database > Estimate Database Size to open the Database Size Estimation dialog.
  2. Click the Include Sub-Packages button and select the tables for which you want to estimate the size.

  3. Click OK.

    The output list displays the estimated database size.

Parent topic: Generating a Database from a PDM