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What are the problems if one were not to normalize? When do these problems surface?
Ans: Database normalization, sometimes considered to as canonical synthesis, is a method for designing relational database tables to minimize duplication of information and, in so doing, to preserve the database against specific types of logical or structural problems, that are data anomalies. For instance, when multiple instances of a given piece of information take place in a table, the possibility exists that these examples will not be kept consistent while the data within the table is updated, leading to a loss of data integrity. A table that is adequately normalized is less vulnerable to problems of this type, as its structure reflects the basic assumptions for while multiple instances of similar information should be denoted by a single instance only.
What is a Name? A user-supplied name is used for identity. This form of identity is used for files in file systems. The user gives every file a name that uniquely identifies it
There are two major types of fragmentation: Horizontal& Vertical. Horizontal fragments, as the name suggests are subsets of tuples and vertical fragments are subsets of attributes
Consider the relation PERSON. If you want to display details of persons having age less than or equal to 30 than the select operation will be used as follows: σ AGE The resu
What are the two main goals of parallelism? Load -balance multiple small accesses, so that the throughput of such accesses enhances. Parallelize large accesses so that the res
What is a virtual table that draws its data from the result of an SQL SELECT statement? View is a virtual table that draws its data from the result of an SQL SELECT statement.
Explain about database system structure? Storage manager Authorization and integrity manager Transaction manager File manager Buffer manager Storage manager
Which method of access uses key transformation? A Hash method of access uses key transformation.
Ancestry database records information about family trees . Following information is recorded about each person: FIRSTNAME first name SURNAME surname MNAME maiden name (if
Association as a cache This association must be updated when any new element is added to it, but testing for overlap using association is more efficient. Figure:
What does the extract statement do in extract datasets? The data is written to virtual memory by extract commands.
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