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Security: Data not needed by local applications is not stored at the site, therefore no unnecessary security violations may exist.
But how can we carry out fragmentation? Fragmentation may be carried out as per the following rules:
a) Completeness: This rule makes sure that there is no loss of data while fragmentation. If a relation is decomposed into fragments, then every data item must appear in at least single fragment.
b) Reconstruction: This rule makes sure preservation of functional dependencies. It should be possible to describe a relational operation that will reconstruct the relation from its fragments.
c) Disjointness: A data item that shows in a fragment should not show in any other fragment. Though, a typical fragmentation known as vertical fragmentation is an exception to this rule. In vertical fragmentation the primary key attributes must be repeated to permit reconstruction of original relation.
This rule makes sure minimization of data redundancy. What are the dissimilar types of fragmentation?
With the help of an example display how records can be deleted and updated in QBE. (i) Increase Pay_Rate of employees along with the skill of ‘cook' by 10%. (ii) Delete employee
List any eight applications of DBMS. a) Universities b) Airlines c) Banking d) Credit card transactions e) Tele communication f) Sales g)Finance h) Manufac
Serialisability: Any schedule that makes the similar results as a serial schedule is known as a serialisable schedule. But how can a schedule are determined to be serialisable or n
Let us now make the E-R diagram for the student database as per the explanation given in the previous section. We can also states the overall logical structure of a database usi
Consider a relation s over the attributes A and B with the following characteristics: 5,000 tuples with 10 tuples per page A 2-level B+ tree index on attribute
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What is D command work in the respect of QBE? D: It is the command inside QBE to delete tuple(s) from the relation.
What is data independence? Data Independence: Techniques which permit data to be changed without affecting the applications in which procedure it. There are two types of data
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What is a guard condition? Explain it with a suitable example. The guard-condition is a Boolean expression written with respect to parameters of triggering event and attributes
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