1 UPDATE TableReference
2? AS CorrelationName
3 SET
4+ ,
4 Column = Expression
5? WHERE Expression

WHERE

1 TableReference =   Database
2? 
2.0? . DataSourceClause
2.1 . SchemaClause
3 . TableClause

1 DataSourceClause =  
2 DataSourceName
2 { DataSourceExpression }

1 SchemaClause =  
2 SchemaName
2 { SchemaExpression }

1 TableClause =  
2 TableName
2 { TableExpression }