DBMS MCQS
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.