ExtendedTableMetadata xs vxt An extension to VODataService that enables richer descriptions of tables. A detailed description of a logically-related set of tables, supported functions/procedures, and joining tips. A non-standard function or stored procedure that can be used in queries with one or more of the tables in this table set (subject to application or service limitations). No assumptions should be made as to the applicability of this function with table components from other table sets. Any restrictions on the use of this function should be captured in the "description" child element. A tip or recommendation on the columns that can be used to join two tables. Often the two columns represent an explicit primary key column from one table and a foreign key from another; however, these need not be strictly so. A function that can be used in a query (typically in ADQL or SQL). Functions declared in the default catalog and schema are global. The name of the function. A description of what the function does. The data type returned by the function. The unit in which the returned value of the function is measured. A parameter that must be passed to the function. A potential join between two tables. A name to identify the join. A pair of columns, one in each of the two, joined tables, to uses a keys in the join. The fully-qualified name of a column on which to join. The qualification must include the table name, the schema name (unless the table is in the default schema) and the catalog name (unless the table is in the default catalog). A description of the join stating its semantics.