MySQL Database Multiple Choice Questions on “Data Value Categories”.
1. Numbers prefixed with ‘0x’ are in base __________
a) 8
b) 16
c) 32
d) 64
Answer: b
Clarification: In MySQL, there are many numeric datatypes. They include integers and floating points. For example, 34, 12.3, -1.3E11. The numbers that are prefixed with ‘0x’ are in hexadecimal.
2. Hexadecimal numbers cannot be used in scientific notation.
a) True
b) False
Answer: a
Clarification: The scientific notation for real numbers is possible in MySQL. Approximate values are represented as floating point numbers in scientific notation. It consists of a mantissa and exponent.
3. The mantissa in -1.58E5 is __________
a) -1.58
b) 1.58
c) E
d) 5
Answer: a
Clarification: In MySQL, the scientific notation for real numbers is possible. Some values are represented as floating point numbers in scientific notation consisting of a mantissa and exponent.
4. The BIGINT precision is of bit _________
a) 32
b) 64
c) 128
d) 16
Answer: b
Clarification: In MySQL, for the expressions containing only exact values that are all integers, the evaluation uses BIGINT (64 – bit) precision. MySQL evaluates expressions using exact/approximate math.
5. The DECIMAL used for expressions containing only exact values with fractional part is of digit precision _________
a) 32
b) 64
c) 65
d) 16
Answer: c
Clarification: In MySQL, for the expressions containing only exact values and where one or more values have a fractional part, the DECIMAL arithmetic is used with digits of precision equal to 65.
6. If a string is to be converted to a number, it is converted into a _____________
a) double precision floating point
b) single precision floating point
c) decimal integer
d) hexadecimal integer
Answer: a
Clarification: When there is a need to convert a string to a number to evaluate an expression, it is first converted to a double precision floating point value. Then, it can be used to do arithmetic.
7. The bit-field values are prefixed with __________
a) 0b
b) 0bit
c) bit-
d) ‘bit’
Answer: a
Clarification: In MySQL, the bit-field values can be either written as b’value’ or 0bvalue. Here, value is a sequence of digits zero or/and one. For example, b’1010′ and 0b1010 are decimal value 10.
8. A BIT value in a result set is displayed as a binary string.
a) True
b) False
Answer: a
Clarification: In MySQL, the BIT values in the result set are displayed as binary strings. In order to convert them to integers, either a zero is added or the ‘CAST()’ operator is used to cast them.
9. ‘2341’ is a ____________
a) integer
b) floating point
c) hexadecimal
d) string
Answer: d
Clarification: In MySQL, the string values are written by enclosing them within quotes. Values like ‘Alexander’, ‘Kolkata, India’ and ‘2341’ are strings. ‘2341’ looks like an integer but is a string.
10. If ANSI_QUOTES is enabled, MySQL treats the double quotes as ________________
a) identifier-quoting character
b) string-quoting character
c) hexadecimal
d) string
Answer: a
Clarification: The SQL standard specifies the single quotes so that statements are portable across database engines. If ANSI_QUOTES is enabled, MySQL treats the double quotes as identifier-quoting character.