![]() Will have to scan all the data before finding every employee named John. It is a list of values from a column with a reference to the position where they can be found in the column.įor example, consider that we want to select every employee with the name of John. In a relational database, the index is similar to a table of contents in a book. The virtual foreign key can be used only for design purposes or for relational data editor, which we'll explain later. In this case, no data verification will be done in the database. Virtual means that the foreign key is created only in Db Schema.
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