Adding a new table in an EDB means, as a matter of fact, creating an appropriate table in the data source containing the given EDB. In many cases it is more convenient to perform such an operation using the same program tools which were used for creation of the data source (a DBMS, a spreadsheet program etc.). After the next opening of the EDB in ObjectLand the new table will appear in the list of EDB tables.
There is, however, a possibility to create a new EDB table by means of ObjectLand, not resorting to the use of any other applications. However the process of adding an EDB table differs essentially from adding an internal table of GDB. In order to create a table, ObjectLand is to generate an SQL statement 'CREATE' and to send it via ODBC to the server program managing the data source. To deliver a user from immediate dealing with the SQL language, there is an ObjectLand wizard of adding tables which allows specifying parameters of the table being created in a more convenient way, and then the corresponding 'CREATE' statement if generated automatically.
One should take into consideration that in ObjectLand there are two variants of correspondence between EBD tables and tables in the data source. In one variant, a 'TABLE' object in the source correspond to the EDB table, but in other variant, the EDB table is based on a 'VIEW' object stored in the data source. The notion of “view” in terms of databases roughly corresponds to the notion of “query” in ObjectLand, i.e. a view is built on the base of one or more tables of the source with the use of such operations as joining, sorting, excluding some fields, selecting records on a specified condition etc. However, in ObjectLand a data source 'VIEW' will be considered as a GDB table, not as a query.
Execution of the operation of EDB table adding differs substantially from adding an internal GDB table as described in the chapter 23 “Table structure”, subsection “Creating a table”. If the user executes the menu command Edit+Add with an EDB table selected in the navigation window's pane, then the EDB table adding wizard is launched.
It is easy to understand that the two fundamentally different ways of EDB table creating require specifying quite different parameter sets, so the wizard comprises different page sets in this two cases.
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