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Recent questions tagged databases

0 votes
2 answers
1
Assume transaction $A$ holds a shared lock $R.$ If transaction $B$ also requests for a shared lock on $R.$ It will result in deadlock situation immediately be granted immediately be rejected be granted as soon as it is released by $A$
asked Apr 1 in Databases Lakshman Patel RJIT 156 views
0 votes
1 answer
2
Given relations $R(w,x)$ and $S(y,z),$ the result of SELECT DISTINCT $w,x$ from $R,S$ $R$ has no duplicates and $S$ is non-empty $R$ and $S$ have no duplicates $S$ has no duplicates and $R$ is non-empty $R$ and $S$ has the same number of tuples
asked Apr 1 in Databases Lakshman Patel RJIT 120 views
0 votes
2 answers
3
For a database relation $R(a,b,c,d)$ where the domains of $a,b,c$ and $d$ include only atomic values, only the following functional dependencies and those that can be inferred from them hold. $a \rightarrow c$ $b \rightarrow d$ The relation is in First normal form but not in second normal form Second normal form but not in third normal form Third normal form None of the above
asked Apr 1 in Databases Lakshman Patel RJIT 109 views
1 vote
1 answer
4
0 votes
1 answer
5
When transaction $Ti$ requests a data item currently held by $Tj,Ti$ is allowed to wait only if it has a time stamp smaller than that of $Tj$ (that is $Ti$ is order than Tj). Otherwise, $Ti$ is rolled back (dies). This is Wait-die Wait-wound Wound-wait Wait
asked Apr 1 in Databases Lakshman Patel RJIT 96 views
0 votes
2 answers
6
When transaction $Ti$ requests a data item currently held by $Tj,Ti$ is allowed to wait only if it has a timestamp smaller than that of $Tj$ (that is $Ti$ is order than Tj). Otherwise, $Ti$ is rolled back (dies). This is Wait-die Wait-wound Wound-wait Wait
asked Apr 1 in Databases Lakshman Patel RJIT 97 views
0 votes
0 answers
7
Given relations $R(w,x)$ and $S(y,z),$ the result of SELECT DISTINCT $w,x$ from $R,S$ $R$ has no duplicates and $S$ is non-empty $R$ and $S$ have no duplicates $S$ has no duplicates and $R$ is non-empty $R$ and $S$ has the same number of tuples
asked Apr 1 in Databases Lakshman Patel RJIT 72 views
0 votes
1 answer
10
Assume transaction $A$ holds a shared lock $R.$ If transaction $B$ also requests for a shared lock on $R.$ It will result in deadlock situation immediately be granted immediately be rejected be granted as soon as it is released by $A$
asked Apr 1 in Databases Lakshman Patel RJIT 72 views
0 votes
1 answer
11
Table employees has $10$ records. It has a non-NULL SALARY column which is also UNIQUE. The SQL statement SELECT COUNT(*) FROM EMPLOYEE WHERE SALARY > ALL (SELECT SALARY FROM EMPLOYEE); $10$ $9$ $5$ $0$
asked Apr 1 in Databases Lakshman Patel RJIT 97 views
1 vote
1 answer
12
0 votes
1 answer
13
0 votes
1 answer
14
0 votes
2 answers
15
0 votes
1 answer
16
In functional dependency between two sets of attribute $A$ and $B$ then set of attributes $A$ of database is classified as: top right side down left side left hand side right hand side
asked Mar 31 in Databases Lakshman Patel RJIT 147 views
0 votes
1 answer
17
Which type of Statement can execute parameterized queries? PreparedStatement ParameterizedStatement ParameterizedStatement and CallableStatement All kinds of Statements
asked Mar 31 in Databases Lakshman Patel RJIT 216 views
0 votes
1 answer
18
0 votes
1 answer
19
Which one of the following statements about normal forms is FALSE? BCNF is stricter than $3$NF. Lossless, dependency-preserving decomposition into BCNF is always possible. Lossless, dependency-preserving decomposition into $3$NF is always possible. Any relation with two attributes is BCNF.
asked Mar 31 in Databases Lakshman Patel RJIT 129 views
0 votes
1 answer
20
If attribute of relation schema $R$ is member of some candidate key then this type of attributes are classified as: atomic attribute candidate attribute non-prime attribute prime attribute
asked Mar 31 in Databases Lakshman Patel RJIT 97 views
0 votes
1 answer
21
0 votes
2 answers
25
0 votes
1 answer
26
If an SQL query involves NOT,AND,OR with no parenthesis NOT will be evaluated first; AND will be evaluated second; OR will be evaluated last. NOT will be evaluated first; OR will be evaluated second; AND will be evaluated last. AND will be evaluated first; OR will be evaluated second;NOT will be evaluated last. The order of occurrence determines the order of evaluation.
asked Mar 30 in Databases Lakshman Patel RJIT 120 views
0 votes
1 answer
27
1 vote
4 answers
28
Consider following schedules involving two transactions: $S_{1}: \: r_{1}(X);r_{1}(Y);r_{2}(X);r_{2}(Y);w_{2}(Y);w_{1}(X)$ $S_{2}: \: r_{1}(X);r_{2}(X);r_{2}(Y);w_{2}(Y);r_{1}(Y);w_{1}(X)$ Which of the ... . $S_1$ is conflict serializable and $S_2$ is not conflict serializable $S_1$ is not conflict serializable and $S_2$ is conflict serializable Both $S_1$ and $S_2$ are not conflict serializable
asked Mar 24 in Databases jothee 409 views
1 vote
1 answer
29
Let $pk(R)$ denotes primary key of relation $R$. A many-to-one relationship that exists between two relation $R_1$ and $R_2$ can be expressed as follows: $pk(R_2)\rightarrow pk(R_1)$ $pk(R_1)\rightarrow pk(R_2)$ $pk(R_2)\rightarrow R_1 \cap R_2$ $pk(R_1)\rightarrow R_1 \cap R_2$
asked Mar 24 in Databases jothee 136 views
0 votes
3 answers
30
For database relation $R(A,B,C,D)$ where the domains of $A,B,C$ and $D$ include only atomic values, only the following functional dependencies and those that can be inferred from them are: $A \rightarrow C$ $B \rightarrow D$ The relation $R$ is in First ... well as in second normal form Second normal form but not in third normal form. Both in second normal form as well as in third normal form.
asked Mar 24 in Databases jothee 204 views
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