The VisXpert database can be extended to include any data structure of its own. To do this, use the SQL Server Management Studio Express. In the database, see Tables for a list of all tables. The database contains system tables and data structures of some VisXpert modules. System tables usually carry the prefix “SYS”, for example, the VisXpert tables have the prefixes “AL” (reporting system) or “BAS” (basic tables). For clarity, you should use the prefix “USER Data Table” (UDT) or another uniform identifier for project-specific tables, such as “UDT_RECIPE” for a recipe table.
Add your own tables via the Object Inspector (right mouse button on tables, menu item New Table).
Use the table designer to define the structure of the table
:
- Column Name: Column name (usually all characters capitalized, underscores as separators, no spaces, e.g. COLUMN_NAME)
- Data Type: Data type—for example, int for integer values, float for floating point. Strings are usually recommended for the type nvarchar (Unicode string), because for nchar columns the strings are generally filled with spaces up to the defined string length.
- Allow Nulls: determines whether empty field values are allowed
- In the Properties window, you can find additional properties for the currently selected column, which are usually left at the default values.
to allow indexed access to table rows over an integer index use the int data type for the first column and right-click the blank field at the very beginning of the row with set primary key to define this column as a primary key, ensuring that the field values used are unique while gaining faster access when searching for a row with a specific ID :
To change the table structure later, select the Modify function for the table in the Object Inspector. With the Open Table you open a data grid to view or edit the contents of the table.
If you need multiple tables or relationships between individual tables, it is a good way to create a new data diagram (in the Object Inspector – Database Diagrams – New Database Diagram entry). Existing tables can be inserted into the new chart—for a new blank chart, close the dialog with Close. Inserting and changing tables in the chart is done using the right-click functions.
