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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?
Saving Derived Attributes to Avoid Re-computation As discussed, "redundancy means duplication of exact data". But, if multiple copies of same data are present in the system,
These are interactive interfaces, graphical that hide the difficulty of the DBMS and query language behind an intuitive, simple to understand, and convenient interface. This permit
Describe an data dictionary? A data dictionary is a data structure which keeps meta data about the structure of the database ie. the schema of the database.
explain in detail about time stamp orderting/
Define instance and schema? Instance: Collection of data kept in the data base at a particular moment is known as an Instance of the database. Schema: The o
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
This project requires you to perform a systems analysis and then design a system solution using database software. Ace Auto Dealers specializes in selling new vehicles from Subaru.
Explain trigger? Trigger: A database trigger is procedural code which is automatically executed within response to certain events on a particular table in a database. Trigger
Three Level Architecture of DBMS or Logical DBMS Architecture The logical architecture defines how data in the database is perceived by users. It is not deals with how the da
example of bank
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