A method performed by a database management system including a structured query language SQL engine, an execute engine, and a storage engine for performing query computation in a database, comprising: receiving (S610), by the SQL engine, from a client , a structured query language, SQL, statement for performing query computation on an object in the database, the object being referred in the SQL statement by a corresponding object description information; processing, by the SQL engine, the SQL statement to generate an execute plan; extracting (S620), by the execute engine, a stored object identifier, ID, of the object from a data store, wherein the object identifier of the object is obtained by encoding the object, by calling an encoding interface with the object description information as input, in a global dictionary table, stored by the storage engine, the global dictionary table comprising an object ID and object description information of each object in a global object sample space, the object ID of each object being unique in the global object sample space, the object ID and the object description information of the object being in a one-to-one mapping relationship in the global dictionary table, and the global object sample space being composed of a plurality of correlated object sample spaces in the database, wherein a same type of objects in the database compose an object sample space, and the objects comprising a tuple and the plurality of correlated object sample spaces comprise at least two correlated columns in the database, and the at least two columns compose the global object sample space; and performing (S630), by the executing engine, query computation based on the execute plan by directly using the object ID of the object, to generate a query result, wherein directly using the object ID of the object is performed by replacing the object description information with said object ID, and returning the query result to the client . receiving (S610), by the SQL engine, from a client , a structured query language, SQL, statement for performing query computation on an object in the database, the object being referred in the SQL statement by a corresponding object description information; processing, by the SQL engine, the SQL statement to generate an execute plan; extracting (S620), by the execute engine, a stored object identifier, ID, of the object from a data store, wherein the object identifier of the object is obtained by encoding the object, by calling an encoding interface with the object description information as input, in a global dictionary table, stored by the storage engine, the global dictionary table comprising an object ID and object description information of each object in a global object sample space, the object ID of each object being unique in the global object sample space, the object ID and the object description information of the object being in a one-to-one mapping relationship in the global dictionary table, and the global object sample space being composed of a plurality of correlated object sample spaces in the database, wherein a same type of objects in the database compose an object sample space, and the objects comprising a tuple and the plurality of correlated object sample spaces comprise at least two correlated columns in the database, and the at least two columns compose the global object sample space; and performing (S630), by the executing engine, query computation based on the execute plan by directly using the object ID of the object, to generate a query result, wherein directly using the object ID of the object is performed by replacing the object description information with said object ID, and returning the query result to the client . <EOS>