____ First proposed the process of normalization.
Answer: C
Correct answer: Edgar F. Codd
E. F. Codd, who invented the relational model at IBM in 1970, also introduced normalisation and defined the first three normal forms.
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Data independence means
Answer: D
Correct answer: both B and C
Data independence has two halves: physical independence means programs do not depend on how the data is stored, and logical independence means they survive changes to the logical structure. Both are meant by the term, which is why the two options are taken together.
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For using a specific database, the ______ command is used.
Answer: A
Correct answer: use database
The USE statement, followed by the database name, makes that database the current one for subsequent statements.
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A _____ is used to define overall design of the database
Answer: D
Correct answer: schema
A schema is the definition of the whole database structure - its tables, their columns and the constraints between them. A data definition language is what the schema is written in, which is not the same as the schema itself.
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Which of the following is not comparison operator?
Answer: C
Correct answer: =<
The comparison operators are \(=\), \(<\), \(>\), \(<=\), \(>=\) and \(<>\). The form =< has its symbols reversed and is not valid; the correct spelling is \(<=\).
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Key to represent relationship between tables is called
Answer: C
Correct answer: foreign key
A foreign key is a column whose values must appear as a primary key in another table, and that requirement is what represents the relationship between the two. A primary key identifies rows within one table only.
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An outstanding functionality of SQL is its support for automatic_____ to the target data.
Answer: B
Correct answer: navigation
In older network and hierarchical systems the programmer had to navigate to the data record by record. SQL is declarative: the query says what is wanted and the system works out how to reach it, which is what automatic navigation means.
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Grant and revoke are _____ statements.
Answer: B
Correct answer: DCL
GRANT and REVOKE control who may do what, so they belong to the Data Control Language. DDL defines structures, DML manipulates data, and TCL manages transactions.
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______is a special type of integrity constraint that relates two relations & maintains consistency across the relations.
Answer: B
Correct answer: Referential Integrity Constraints
A referential integrity constraint links two relations: every value of the foreign key in one must exist as a primary key value in the other. That is what keeps the two tables consistent with each other; domain and entity constraints apply within a single relation.
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DBMS helps achieve
Answer: C
Correct answer: Both A and B
Both follow from holding the data in one managed store: control of the data is centralised in the DBMS rather than scattered among programs, and because programs address the data through the DBMS they no longer depend on how it is stored.
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