Updating olap dimensions accommodating differences variations in differentiated literacy instruction
Thus, Consistent Query Answering (CQA) for first-order queries is translated into cautious reasoning under the stable models semantics.
The use of logic programs does not exceed the intrinsic complexity of CQA.
In practice, dimension updates are often needed to adapt the warehouse to changing re uirements.
Some of them, the updating models =-=[1,2,7,8]-=-, focus on mapping data into the most recent version of the structure, whereas tracking history models [3,5,6,11,14] keep trace of evolutions of the system. In practice, dimension updates are often needed to adapt the warehouse to changing re uirements.
In earlier work, we defined a taxonomy for these dimension updates and a minimal set of operators to perform them.
Dimensions are considered as the static part of the data warehouses, whereas the facts are considered as the dynamic part, so that the update operations affect mainly the fact tables. A DW is composed by a set of dimensions that reflect the way the data is structured, and the facts that correspond to quantitative data related wit ..." Abstract.
However, in =-=[50, 51]-=- it was shown that dimensions can be updated; dimensions constraints can be violated; and therefore, MDWs may become inconsistent wrt them, affecting the evaluation of 33squeries. A Data Warehouse (DW) is a data repository that organizes and physically integrates data from multiple sources under special kinds of schemas.