Please keep at least one language enabled. || కనీసం ఒక భాషను ఎంచుకోండి.
Question 1
ప్రశ్న 1
What is the primary purpose of assigning a data type to a field or column in a database?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A data type defines the nature of values that a database column is intended to store, such as numeric, character, date/time or binary data.
• The selected type also affects the operations and validation applicable to those values.
• Uniqueness requires an appropriate key or UNIQUE constraint; it is not guaranteed merely by selecting a data type.
• The selected type also affects the operations and validation applicable to those values.
• Uniqueness requires an appropriate key or UNIQUE constraint; it is not guaranteed merely by selecting a data type.
వివరణ:
Question 2
ప్రశ్న 2
A database must store a person's Date_of_Birth so that date comparisons and date-related operations can be performed correctly. Which field type is most appropriate?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A date or date/time data type is specifically intended for temporal values.
• It allows a DBMS to interpret the value as a date and perform valid date comparisons and date-related operations.
• Storing dates merely as unrestricted text can permit inconsistent formats and makes reliable date processing more difficult.
• It allows a DBMS to interpret the value as a date and perform valid date comparisons and date-related operations.
• Storing dates merely as unrestricted text can permit inconsistent formats and makes reliable date processing more difficult.
వివరణ:
Question 3
ప్రశ్న 3
A financial database must store an amount such as 1250.75 and exact decimal arithmetic is required. Which category of data type is generally the most appropriate?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• DECIMAL and NUMERIC are exact numeric types designed to represent decimal values with defined precision and scale.
• They are appropriate when exact decimal representation is required, such as many monetary calculations.
• Floating-point types are approximate numeric types and can introduce representation or rounding differences.
• They are appropriate when exact decimal representation is required, such as many monetary calculations.
• Floating-point types are approximate numeric types and can introduce representation or rounding differences.
వివరణ:
Question 4
ప్రశ్న 4
A PERSON table must store names whose lengths vary from one person to another. Which type of field is generally most suitable?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Character-string types are intended for textual data such as names.
• A variable-length character type is particularly suitable when the number of characters differs among stored values.
• Date/time and Boolean types represent different categories of data.
• A variable-length character type is particularly suitable when the number of characters differs among stored values.
• Date/time and Boolean types represent different categories of data.
వివరణ:
Question 5
ప్రశ్న 5
A database application needs to store a digital photograph as the actual binary contents of the image rather than merely storing its filename. Which general type of database field is most appropriate?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Binary data types are intended for sequences of bytes rather than ordinary character or numeric values.
• Images and similar files can be stored using suitable binary or large-object binary types supported by the DBMS.
• An integer or Boolean field cannot directly represent the complete byte contents of a photograph.
• Images and similar files can be stored using suitable binary or large-object binary types supported by the DBMS.
• An integer or Boolean field cannot directly represent the complete byte contents of a photograph.
వివరణ:
Question 6
ప్రశ్న 6
A database field named Is_Verified must store only a logical two-state value such as Yes/No or True/False. Which general field type is most appropriate?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Boolean or equivalent logical data types represent two-state logical values such as True/False or Yes/No.
• The exact type name can vary between database products.
• Date, binary and unrestricted text fields do not express the intended logical meaning as directly.
• The exact type name can vary between database products.
• Date, binary and unrestricted text fields do not express the intended logical meaning as directly.
వివరణ:
Question 7
ప్రశ్న 7
An AGE field should contain numerical ages rather than alphabetic entries such as 'Twenty'. Which database design choice most directly establishes the basic type of data that the field should accept?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A numeric data type establishes that the AGE field is intended to contain numeric values rather than arbitrary text.
• Additional constraints can then be added if a particular valid age range must also be enforced.
• Selecting an appropriate field type is therefore a basic first step toward consistent data entry.
• Additional constraints can then be added if a particular valid age range must also be enforced.
• Selecting an appropriate field type is therefore a basic first step toward consistent data entry.
వివరణ:
Question 8
ప్రశ్న 8
A CASE table requires every record to contain a Case_ID value. Which integrity constraint most directly prevents Case_ID from being left without a value?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A NOT NULL constraint requires the specified column to contain a value rather than NULL.
• It is appropriate for fields that must never be left unspecified.
• A foreign key controls references between tables, while ORDER BY concerns result ordering.
• It is appropriate for fields that must never be left unspecified.
• A foreign key controls references between tables, while ORDER BY concerns result ordering.
వివరణ:
Question 9
ప్రశ్న 9
An employee database requires that no two stored Employee_Code values be the same. Which constraint is specifically intended to enforce this rule?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A UNIQUE constraint prevents duplicate values, or duplicate combinations of values, according to the DBMS's constraint rules.
• NOT NULL ensures that a value is present but does not by itself prevent two rows from containing the same value.
• A DEFAULT merely supplies a value when an explicit one is not provided.
• NOT NULL ensures that a value is present but does not by itself prevent two rows from containing the same value.
• A DEFAULT merely supplies a value when an explicit one is not provided.
వివరణ:
Question 10
ప్రశ్న 10
A database field Age must contain values only from 18 through 60 inclusive. Which type of integrity rule most directly expresses this condition?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A CHECK constraint requires stored values to satisfy a specified logical condition.
• The condition Age >= 18 and Age <= 60 directly expresses the permitted range stated in the question.
• A numeric data type alone establishes that Age is numeric but does not necessarily restrict it to this particular interval.
• The condition Age >= 18 and Age <= 60 directly expresses the permitted range stated in the question.
• A numeric data type alone establishes that Age is numeric but does not necessarily restrict it to this particular interval.
వివరణ:
Question 11
ప్రశ్న 11
Which integrity mechanism is most directly responsible for ensuring that each row of a table has a unique, non-NULL identifier when an appropriate key is defined?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A primary key uniquely identifies every row of a table.
• Primary-key values must be unique and cannot be NULL.
• This supports entity integrity by preventing rows from lacking a valid identifying key.
• Primary-key values must be unique and cannot be NULL.
• This supports entity integrity by preventing rows from lacking a valid identifying key.
వివరణ:
Question 12
ప్రశ్న 12
EMPLOYEE.Department_ID is a foreign key referencing DEPARTMENT.Department_ID. Which basic integrity principle ensures that a non-NULL department reference corresponds to a valid referenced department?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Referential integrity maintains consistency between related parent and child tables.
• A foreign-key constraint requires applicable non-NULL child key values to correspond to valid referenced key values.
• This prevents records from referring to nonexistent parent records.
• A foreign-key constraint requires applicable non-NULL child key values to correspond to valid referenced key values.
• This prevents records from referring to nonexistent parent records.
వివరణ:
Question 13
ప్రశ్న 13
A database stores the same district as 'Hyderabad', 'HYDERABAD', 'Hyd' and 'Hyderabad District' even though all entries are intended to represent one standardized value. What problem is most directly illustrated?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Multiple representations of the same intended fact can make searching, counting and reporting unreliable.
• Consistent data-entry rules, controlled values or appropriate validation can reduce this problem.
• The issue is logical inconsistency in stored data rather than hardware or compression.
• Consistent data-entry rules, controlled values or appropriate validation can reduce this problem.
• The issue is logical inconsistency in stored data rather than hardware or compression.
వివరణ:
Question 14
ప్రశ్న 14
A character field is defined to permit a maximum of 10 characters. What is the main purpose of this field-length rule?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A maximum-length definition restricts how much character data the field is intended to accept.
• A maximum of 10 does not necessarily mean that every stored value must contain exactly 10 characters.
• Length control is different from uniqueness and numeric-type enforcement.
• A maximum of 10 does not necessarily mean that every stored value must contain exactly 10 characters.
• Length control is different from uniqueness and numeric-type enforcement.
వివరణ:
Question 15
ప్రశ్న 15
In basic database terminology, what does NULL represent?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• NULL is used to represent the absence of a known or applicable value.
• It should not automatically be interpreted as the numeric value zero.
• Constraints such as NOT NULL can be used when a database design requires a value to be present.
• It should not automatically be interpreted as the numeric value zero.
• Constraints such as NOT NULL can be used when a database design requires a value to be present.
వివరణ:
Question 16
ప్రశ్న 16
Which database-design approach best supports basic data integrity for a field that must contain a number from 1 to 100 and must never be left NULL?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• The numeric data type establishes the basic kind of data expected.
• NOT NULL ensures that a value is supplied, while a CHECK condition can restrict that value to the required 1–100 range.
• Combining suitable types and constraints provides stronger integrity than relying only on user behaviour.
• NOT NULL ensures that a value is supplied, while a CHECK condition can restrict that value to the required 1–100 range.
• Combining suitable types and constraints provides stronger integrity than relying only on user behaviour.
వివరణ:
Question 17
ప్రశ్న 17
Consider the following statements about database data types:
1. A data type helps define the kind of values a field can contain.
2. Exact numeric types are appropriate when exact decimal representation is required.
3. Character data types can store only numerical digits.
4. Date/time types are designed for temporal values.
Which statements are correct?
1. A data type helps define the kind of values a field can contain.
2. Exact numeric types are appropriate when exact decimal representation is required.
3. Character data types can store only numerical digits.
4. Date/time types are designed for temporal values.
Which statements are correct?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Statements 1, 2 and 4 correctly describe the purposes of data types and major type categories.
• Statement 3 is false because character types are designed to store character strings, which can include letters and other permitted characters as well as digits.
• Therefore Statements 1, 2 and 4 are the correct combination.
• Statement 3 is false because character types are designed to store character strings, which can include letters and other permitted characters as well as digits.
• Therefore Statements 1, 2 and 4 are the correct combination.
వివరణ:
Question 18
ప్రశ్న 18
Assertion (A): Database constraints can improve the consistency and validity of stored data.
Reason (R): Constraints such as NOT NULL, UNIQUE, CHECK and FOREIGN KEY can reject data that violates defined database rules.
Choose the correct answer.
Reason (R): Constraints such as NOT NULL, UNIQUE, CHECK and FOREIGN KEY can reject data that violates defined database rules.
Choose the correct answer.
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Database constraints specify rules that stored data must satisfy.
• NOT NULL, UNIQUE, CHECK and FOREIGN KEY constraints each enforce particular forms of integrity.
• Both statements are true, and the Reason correctly explains how constraints improve data consistency and validity.
• NOT NULL, UNIQUE, CHECK and FOREIGN KEY constraints each enforce particular forms of integrity.
• Both statements are true, and the Reason correctly explains how constraints improve data consistency and validity.
వివరణ:
Question 19
ప్రశ్న 19
Match List I with List II:
List I
(a) Integer/Numeric type
(b) Character-string type
(c) Date/time type
(d) Boolean/logical type
List II
1. Names and other textual values
2. True/False or Yes/No values
3. Whole-number or other appropriate numerical values
4. Dates and times
Choose the correct matching code.
List I
(a) Integer/Numeric type
(b) Character-string type
(c) Date/time type
(d) Boolean/logical type
List II
1. Names and other textual values
2. True/False or Yes/No values
3. Whole-number or other appropriate numerical values
4. Dates and times
Choose the correct matching code.
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Numeric types represent numerical values, giving (a)-3, while character-string types represent textual values, giving (b)-1.
• Date/time types represent temporal values, giving (c)-4.
• Boolean or equivalent logical types represent two-state values such as True/False, giving (d)-2.
• Date/time types represent temporal values, giving (c)-4.
• Boolean or equivalent logical types represent two-state values such as True/False, giving (d)-2.
వివరణ:
Question 20
ప్రశ్న 20
A complaint database requires Status to contain only one of three standardized values: 'Open', 'In Progress' or 'Closed'. Users currently enter variations such as 'OPEN', 'Close', 'Completed' and 'Cls', causing unreliable reports. Which design change best improves consistency?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Restricting the field to a controlled set of approved values prevents multiple inconsistent representations of the same status categories.
• A CHECK rule or controlled lookup/domain design can enforce the permitted choices according to the DBMS being used.
• Increasing field length or duplicating the same data would not solve the consistency problem.
• A CHECK rule or controlled lookup/domain design can enforce the permitted choices according to the DBMS being used.
• Increasing field length or duplicating the same data would not solve the consistency problem.
వివరణ:
Answer Key సమాధానాల పట్టిక
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Question 1 ప్రశ్న 1Answer: B. To define the kind of values the field can store and the operations that can validly be performed on those values సమాధానం: B.
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Question 2 ప్రశ్న 2Answer: D. Date or date/time type సమాధానం: D.
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Question 3 ప్రశ్న 3Answer: A. An exact numeric type such as DECIMAL or NUMERIC సమాధానం: A.
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Question 4 ప్రశ్న 4Answer: C. Variable-length character field such as VARCHAR సమాధానం: C.
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Question 5 ప్రశ్న 5Answer: C. Binary or large-binary field సమాధానం: C.
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Question 6 ప్రశ్న 6Answer: A. Boolean or equivalent logical type సమాధానం: A.
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Question 7 ప్రశ్న 7Answer: D. Define AGE using an appropriate numeric data type. సమాధానం: D.
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Question 8 ప్రశ్న 8Answer: B. NOT NULL సమాధానం: B.
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Question 9 ప్రశ్న 9Answer: A. UNIQUE సమాధానం: A.
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Question 10 ప్రశ్న 10Answer: C. A CHECK constraint enforcing Age >= 18 and Age <= 60 సమాధానం: C.
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Question 11 ప్రశ్న 11Answer: B. Primary-key constraint సమాధానం: B.
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Question 12 ప్రశ్న 12Answer: D. Referential integrity సమాధానం: D.
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Question 13 ప్రశ్న 13Answer: D. Data inconsistency caused by non-standardized values సమాధానం: D.
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Question 14 ప్రశ్న 14Answer: B. To prevent values longer than the permitted maximum from being stored in that field సమాధానం: B.
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Question 15 ప్రశ్న 15Answer: C. The absence of a known or applicable stored value సమాధానం: C.
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Question 16 ప్రశ్న 16Answer: A. Use an appropriate numeric data type together with NOT NULL and a suitable CHECK constraint. సమాధానం: A.
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Question 17 ప్రశ్న 17Answer: C. 1, 2 and 4 only సమాధానం: C.
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Question 18 ప్రశ్న 18Answer: D. Both Assertion and Reason are true, and Reason is the correct explanation of Assertion. సమాధానం: D.
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Question 19 ప్రశ్న 19Answer: A. (a)-3, (b)-1, (c)-4, (d)-2 సమాధానం: A.
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Question 20 ప్రశ్న 20Answer: B. Restrict Status to the approved set of values using an appropriate validation rule, CHECK constraint or controlled lookup design. సమాధానం: B.