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What is a flat file database?

  • File with compressed schema
  • UI test file
  • Plain text file storing data
  • SQL format data
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What is the role of a data dictionary?

  • Stores table rows
  • Stores database schema metadata
  • Encrypts columns
  • Defines user roles
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What does NVL() function do in SQL?

  • Returns next value
  • Converts NULL to alternate value
  • Compares strings
  • Merges rows
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What is a surrogate key?

  • Natural identifier
  • Manually entered field
  • System-generated primary key
  • Schema version
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What is a primary key?

  • A duplicate key
  • A unique identifier for records
  • A null field
  • A database name
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Which statement is used to create a new table?

  • ALTER
  • INSERT
  • CREATE TABLE
  • UPDATE
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Which SQL statement is used to update existing data?

  • SELECT
  • UPDATE
  • INSERT
  • DELETE
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What does SQL injection test for?

  • Network bandwidth
  • Security flaws in input fields
  • Query speed
  • Image loading
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How do you ensure data was inserted correctly?

  • UI test
  • Validate from logs
  • Query the DB with SELECT
  • Ask developer
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What does COUNT(*) do?

  • Counts NULLs only
  • Returns total number of rows
  • Excludes duplicates
  • Counts only selected fields
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What is the purpose of the BETWEEN clause?

  • Match exact values
  • Check range of values
  • Search text
  • Group values
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What is the result of RIGHT JOIN without a match?

  • NULLs on left table columns
  • Full join result
  • Error
  • Only matched records
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Which SQL statement is used to retrieve data?

  • UPDATE
  • INSERT
  • SELECT
  • DELETE
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Which datatype is best for storing date/time values?

  • INT
  • DATETIME
  • CHAR
  • FLOAT
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What is latency in database performance?

  • Query length
  • Delay in data access
  • Total rows
  • Index position
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Which clause is used to limit the number of rows returned?

  • COUNT
  • HAVING
  • LIMIT
  • SUM
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What is the result of dividing by zero in SQL?

  • Error
  • Zero
  • NULL
  • Infinity
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What is the first normal form (1NF)?

  • Remove foreign keys
  • No repeating groups or arrays
  • Add redundant data
  • Encrypt columns
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What is a NULL value in a database?

  • A zero
  • An empty string
  • A missing or undefined value
  • A negative number
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What is a composite foreign key?

  • Primary and unique keys
  • Multiple columns referring to another table?s composite key
  • Single column mapping
  • Redundant key
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What is the purpose of rollback testing?

  • Validate delete statements
  • Ensure transactions revert correctly
  • Check logs
  • Test speed
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What is data integrity?

  • UI design accuracy
  • Network strength
  • Accuracy and consistency of data
  • Number of test cases
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What does DML stand for?

  • Data Memory Load
  • Database Management Language
  • Data Manipulation Language
  • Data Module Layer
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What is a view in database?

  • Stored data
  • Virtual table based on a query
  • Schema info
  • SQL user
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Which SQL clause groups records?

  • GROUP BY
  • ORDER BY
  • HAVING
  • WHERE
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What happens when a DELETE statement has no WHERE clause?

  • Only one row is deleted
  • No rows deleted
  • All rows are deleted
  • Syntax error
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What is the difference between CHAR and VARCHAR?

  • CHAR is variable-length
  • VARCHAR uses more memory
  • CHAR is fixed-length, VARCHAR is variable-length
  • No difference
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What is the default sort order in ORDER BY clause?

  • Descending
  • Random
  • Ascending
  • Alphabetical
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Which clause restricts rows before aggregation?

  • HAVING
  • GROUP BY
  • WHERE
  • LIMIT
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Which test ensures foreign keys maintain relationships correctly?

  • Load testing
  • Referential integrity testing
  • UI testing
  • Stress testing
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