Which key uniquely identifies a row in a table?Foreign KeyPrimary KeyComposite KeyCandidate KeyB) Primary KeyPrimary key uniquely identifies each row/record in a table.
SQL stands for:Structured Query LanguageSimple Query LanguageSequential Query LanguageServer Query LanguageA) Structured Query LanguageSQL is used to manage and manipulate relational databases.
Which of the following is a DML command?CREATEALTERINSERTDROPC) INSERTData Manipulation Language includes INSERT, UPDATE, DELETE.
Normalization is used to:Remove redundancySpeed up queriesEncrypt dataCreate triggersA) Remove redundancyNormalization reduces data duplication and maintains integrity.
Which join returns only matching rows from both tables?LEFT JOINRIGHT JOININNER JOINFULL JOINC) INNER JOININNER JOIN returns rows with matching values in both tables.
Which normal form eliminates transitive dependency?1NF2NF3NFBCNFC) 3NF3NF removes transitive dependencies ensuring non-key attributes depend only on keys.
Which SQL command is used to remove a table from a database?DELETEDROPTRUNCATEREMOVEB) DROPDROP permanently removes the table schema and data from the database.
ACID properties in DBMS stand for:ACID properties in DBMS stand for:Atomicity, Consistency, Isolation, DurabilityAllocation, Control, Integrity, DistributionAuthorization, Concurrency, Isolation, DebuggingAtomicity, Clustering, Indexing, DesignA) Atomicity, Consistency, Isolation, DurabilityACID ensures reliable transaction processing in databases.
A foreign key is:Primary key of a tableUnique identifier within the same tableKey from one table referencing primary key of another tableComposite keyC) Key from one table referencing primary key of another tableForeign keys establish referential integrity between related tables.
Which of the following is a non-procedural query language?CSQLPL/SQLPythonB) SQLSQL specifies what data to retrieve rather than how to retrieve it.
Which of the following is a type of database key that uniquely identifies each record?Foreign KeyPrimary KeyComposite KeyCandidate KeyB) Primary KeyPrimary Key uniquely identifies each tuple in a relation.
Which join returns all rows from both tables including unmatched rows?INNER JOINLEFT JOINRIGHT JOINFULL OUTER JOIND) FULL OUTER JOINFull Outer Join returns matching and non-matching rows from both tables.
A transaction that cannot be divided further is called:SerializableAtomicIsolatedDurableB) AtomicAtomicity ensures a transaction is all-or-nothing and cannot be partially executed.
Indexing in a database is used to:Store imagesIncrease query performanceReduce storage costMaintain ACID propertiesB) Increase query performanceIndexes speed up data retrieval by maintaining a sorted reference to table records.
SQL keyword used to sort the result-set is:ORDER BYSORTGROUP BYARRANGEA) ORDER BYORDER BY sorts query results in ascending or descending order.
Which normal form removes partial dependency?1NF2NF3NFBCNFB) 2NF2NF eliminates partial dependency by ensuring full functional dependency on primary key.
Candidate keys are:Primary keys + Foreign keysAll attributes uniquely identifying rowsAlternate keys onlyComposite keys onlyB) All attributes uniquely identifying rowsCandidate keys are all possible unique identifiers for table rows.
Transaction isolation level that allows dirty reads:Read CommittedRead UncommittedRepeatable ReadSerializableB) Read UncommittedRead Uncommitted allows reading uncommitted changes from other transactions.
Trigger in DBMS is:ConstraintPredefined Action on EventPrimary KeyStored Procedure onlyB) Predefined Action on EventTriggers automatically execute when a specified event (INSERT, UPDATE, DELETE) occurs.
SQL clause to group rows:WHEREGROUP BYHAVINGORDER BYB) GROUP BYGROUP BY aggregates rows sharing common values.
A view in SQL is:A virtual tableA physical copy of tableA backup tableA stored procedureA) A virtual tableViews represent query results as virtual tables without storing data.
Deadlock in DBMS happens when:Two transactions wait for each other’s resourcesToo many users query databaseA single query runs slowlyDatabase is corruptedA) Two transactions wait for each other’s resourcesCircular waiting leads to deadlock.
Which of the following ensures no partial or transitive dependency?1NF2NF3NFBCNFC) 3NF3NF removes both partial and transitive dependencies.
Commit operation in DBMS means:Rollback all changesSave changes permanentlySave changes temporarilyClose connectionB) Save changes permanentlyCOMMIT makes all changes permanent in database.
Indexing improves:Insert SpeedDelete SpeedQuery Retrieval SpeedDisk Space UsageC) Query Retrieval SpeedIndexes allow faster search and retrieval operations.
Which SQL command is used to remove a table?DELETEDROPTRUNCATEREMOVEB) DROPDROP removes the entire table definition and data.
Which of the following ensures uniqueness in a table?Foreign KeyPrimary KeyIndexViewB) Primary KeyPrimary key uniquely identifies each row in a table.
Which transaction property ensures system returns to a stable state after failure?ConsistencyIsolationDurabilityAtomicityD) AtomicityAtomicity ensures either full execution or no execution of a transaction.
A clustered index stores:Data rows separately from indexData rows in sorted order of index keyOnly index entriesBackup copiesB) Data rows in sorted order of index keyClustered index sorts and stores table rows according to the index.
Which SQL command is used to change structure of a table?UPDATEALTERMODIFYREVISEB) ALTERALTER command modifies table schema (columns, constraints).
Which key uniquely identifies each record in a table?Foreign keyCandidate keyPrimary keyComposite keyC) Primary keyPrimary key uniquely identifies a row in a table.
The language used to query databases is:HTMLSQLXMLJSONB) SQLSQL is used to manage and query relational databases.
ACID in DBMS stands for:Atomicity, Consistency, Isolation, DurabilityAccuracy, Consistency, Integrity, DependabilityApplication, Control, Isolation, DataAccess, Cache, Index, DataA) Atomicity, Consistency, Isolation, DurabilityACID ensures reliable database transactions.
Which normal form removes transitive dependency?1NF2NF3NFBCNFC) 3NF3NF eliminates transitive dependencies.
ACID property ensuring changes are permanent is:AtomicityConsistencyIsolationDurabilityD) DurabilityDurability guarantees persistence after commit.
Which join returns all rows from both tables with nulls?Inner JoinLeft JoinRight JoinFull Outer JoinD) Full Outer JoinFull outer join returns matching and non-matching rows.
Which command is used to revoke privileges in SQL?DENYREVOKEDROPREMOVEB) REVOKEREVOKE removes user access rights.
A relation with no repeating groups is in:1NF2NF3NF4NFA) 1NF1NF eliminates repeating groups in a relation.
Which of the following ensures no two rows have duplicate values in a column?DEFAULTUNIQUECHECKINDEXB) UNIQUEUNIQUE enforces distinct column values.
Which concurrency control method uses timestamps?LockingValidationTimestamp orderingDeadlock detectionC) Timestamp orderingIt orders transactions using unique timestamps.
Default isolation level in most DBMS:READ UNCOMMITTEDREAD COMMITTEDREPEATABLE READSERIALIZABLEB) READ COMMITTEDPrevents dirty reads.
Candidate key is:Super key with no redundant attributePrimary key onlyForeign keyComposite keyA) Super key with no redundant attributeCandidate keys are minimal super keys.
BETWEEN in SQL is:DDLDMLDCLOperatorD) OperatorBETWEEN checks range in SQL queries.
Weak entity identified by:Primary keyPartial key & strong entityComposite keySurrogate keyB) Partial key & strong entityWeak entities depend on strong entities.
3NF removes:Partial dependencyTransitive dependencyMulti-valued dependencyAll redundancyB) Transitive dependency3NF ensures no non-key depends on non-key.
In SQL, which clause is used to filter records?ORDER BYWHEREGROUP BYHAVINGB) WHEREWHERE filters rows before grouping.
Which indexing method uses a balanced tree?B+ TreeHash indexingSequential indexingBitmap indexingA) B+ TreeB+ trees ensure balanced indexing.
ACID property ensuring no partial transaction execution is:AtomicityConsistencyIsolationDurabilityA) AtomicityTransaction is all-or-nothing.
The SQL command to remove a table permanently is:DELETETRUNCATEDROPREMOVEC) DROPDROP deletes table structure and data.
Which normal form removes transitive dependencies?1NF2NF3NFBCNFC) 3NF3NF ensures no transitive dependency.
In SQL, which clause is used to filter rows?WHEREHAVINGORDER BYGROUP BYA) WHEREWHERE clause filters rows based on conditions.
Which key uniquely identifies a record?Foreign keyPrimary keyCandidate keyComposite keyB) Primary keyA primary key uniquely identifies rows.
ACID property ensures:Transaction safetyQuery speedStorage capacityIndexingA) Transaction safetyACID = Atomicity, Consistency, Isolation, Durability.
Which SQL keyword is used to sort query results?GROUP BYORDER BYHAVINGSELECTB) ORDER BYORDER BY arranges query results in ascending/descending order.
Which of the following is a DCL command?CREATEGRANTSELECTDROPB) GRANTData Control Language commands manage permissions.
Which schedule ensures serializability?Non-conflicting scheduleSerializable scheduleRecoverable scheduleCascading scheduleB) Serializable scheduleSerializable schedules are equivalent to some serial execution.
A weak entity is identified by:Partial key + owner’s primary keyComposite keySurrogate keyCandidate keyA) Partial key + owner’s primary keyWeak entities depend on strong entities for identification.
A database index improves:SecurityAccess speedData redundancyConsistencyB) Access speedIndexes allow faster retrieval of records.
Which concurrency control avoids deadlock?Two-phase lockingTimestamp orderingStrict lockingNoneB) Timestamp orderingTimestamp ordering ensures transactions follow time order.
Which SQL command is used to remove duplicate rows?UNIQUEDISTINCTPRIMARYCLEANB) DISTINCTDISTINCT removes duplicates in SELECT queries.
Which key uniquely identifies a record in a relation?Foreign KeyCandidate KeyPrimary KeyAlternate KeyC) Primary KeyA primary key uniquely identifies each record in a table.
The SQL GROUP BY clause is used with:Aggregate functionsConstraintsTransactionsIndexesA) Aggregate functionsGROUP BY groups rows for aggregate calculations like SUM, AVG.
What is the main purpose of a database index?Reduce redundancyImprove query performanceIncrease normalizationManage transactionsB) Improve query performanceIndexes allow faster searching and retrieval.
In ER diagrams, a diamond shape represents:AttributeEntityRelationshipWeak EntityC) RelationshipRelationships between entities are represented with diamonds.
In ER model, attributes are represented by:RectangleEllipseDiamondLineB) EllipseAttributes are shown as ellipses.
Which normal form eliminates multi-valued dependencies?1NF2NF3NF4NFD) 4NF4NF removes multi-valued dependencies.
Which of these is not a key in DBMS?Candidate KeyPrimary KeyForeign KeyParallel KeyD) Parallel KeyParallel key doesn’t exist in DBMS.
In relational algebra, σ represents:ProjectionSelectionJoinUnionB) Selectionσ denotes selection of rows.
ACID property “I” stands for:IntegrationIsolationInheritanceIndexingB) IsolationTransactions execute independently.
In relational databases, which operation is used to combine tuples from two relations based on a common attribute?ProjectionJoinUnionSelectionB) JoinA join operation merges rows from two or more tables based on a related column, enabling queries across multiple relations.