HackerRank DBMS & SQL Quiz- 1

Savepoint is used to temporarily save a transaction so that you can rollback to that point whenever required.

SDL stands for Storage Definition Language. SDL matter is almost anything that’s not specified by SQL standard. It is different in every DBMS which specifies anything to do with how or where data in relevant table is stored. It’s applications are as follows :

• Used to define internal schema.


• It defines physical structure of database.


• The order of fields.


• Bytes per field will be used.


• How records will be accesses etc.


• The mapping between two schema may also be defined.

The attribute closure of,

RS= RS

Hence the attribute closures of 

PRS=PQRST

QRS=PQRST

RST=PQRST

Hence the candidate keys are (PRS,QRS,RST)

So, the prime attributes are = P,Q,R,S,T

So, in the dependency P->Q both P and Q are prime attributes So, the table is not in BCNF and there is no transitive dependencies so, the table is in 3NF

It adds value ‘10 Null Null 45000’ to the last row of the table

Drop is DDL command

Update is DML command

CSS is a declarative language

Commit is a TCL command

Truncate removes all the tuples of the table but it don’t removes the definition of a table.

A table which is already in 3NF Shouldn't have any multivalued attribute, partial dependency and transitive dependency.

Following statements about the wait-die Scheme is true

1. It is a Deadlock prevention mechanism


2. If the older transaction needs some resource locked by a newer transaction then the older transaction will wait.


3. If a younger transaction is waiting for some resource locked by an old transaction then the younger transaction is killed and restarted with a very minute delay with the same timestamp.

If the log of  a transaction Ti contains <Ti start> and <Ti commit> or <Ti abort> then this transaction should be redone.

All the statements are true about metadata.