XML Schema Complete Reference, The

24.14. sequence Element

The sequence element describes a required ordered set of element types. From a database schema perspective, if the minOccurs and maxOccurs are both 1 for the sequence and for each element type, the database representation maps to a table with a series of columns that are all required. If an underlying element type is complex, it requires a foreign key relationship. If the minOccurs is 0, the column becomes optional; if the maxOccurs is greater than 1, a separate table is required. Listing 24.15 implements the siDBCatalogEntryType to illustrate a number of these possibilities.

Listing 24.15. A siDBCatalogEntryType XML Schema Document Fragment That Is a Simplification of catalogEntryType

<xsd:complexType name="siDBBusinessType" ...