SQL plays a very important role in the data base area,so its standardization attracts the at-tention of data base cooperation and the related standard organizations. Seven years later form the emer-gence of SQL-92,the...SQL plays a very important role in the data base area,so its standardization attracts the at-tention of data base cooperation and the related standard organizations. Seven years later form the emer-gence of SQL-92,the SQL's new version SQL:1999 at last conies up at 1999. This paper describes themain contents of SQL: 1999 ,especially the changes to SQL-92 ,including the new added data types ,com-paring predicates ,semantics ,security ,trigger mechanism and other object relational characteristics,suchas user defined structured type ,stored procedure, function,method, typed relation and reference type.Some under developing parts and the future works are also described.展开更多
For a quantized enveloping algebra of finite type, one can associate a natural monomial to a dominant weight. We show that these monomials for types A5 and D4 are semitight(i.e., a Z-linear combination of elements in ...For a quantized enveloping algebra of finite type, one can associate a natural monomial to a dominant weight. We show that these monomials for types A5 and D4 are semitight(i.e., a Z-linear combination of elements in the canonical basis) by a direct calculation.展开更多
文摘SQL plays a very important role in the data base area,so its standardization attracts the at-tention of data base cooperation and the related standard organizations. Seven years later form the emer-gence of SQL-92,the SQL's new version SQL:1999 at last conies up at 1999. This paper describes themain contents of SQL: 1999 ,especially the changes to SQL-92 ,including the new added data types ,com-paring predicates ,semantics ,security ,trigger mechanism and other object relational characteristics,suchas user defined structured type ,stored procedure, function,method, typed relation and reference type.Some under developing parts and the future works are also described.
文摘For a quantized enveloping algebra of finite type, one can associate a natural monomial to a dominant weight. We show that these monomials for types A5 and D4 are semitight(i.e., a Z-linear combination of elements in the canonical basis) by a direct calculation.
