Question

8. All of the following are algorithms to evaluate join, except: a. Nested loop b. Index-nested loop c. Sort-merge d. B+-tree 9. All the following DDL commands, except: a. Create C. Drop b.Select d. Alter 10. The following rule must be maintained by the DBMS to ensure data consistency: a. All of these b. Referential integrity constraints C. Attribute domain constraints d. Entity integrity constraints

Answer 1

Bu All of the following are algorithms to evaluate Join, except a) Nested loop b) Index loop c) Salt - merge la B+-tree And :- We know we have three types of going Inner, Outer and Semi Joing to evaluate this Toins we have loir aloolilthms which are Nested Loop Join : This is the simplest way of how a voin can be executed. It is a naive algorithm which uses two nested loops, one Loop over one relation and second over another. For each pow pairs Join condition is evaluated: Pairs which Satisfy the condition are returned. Index loop join :- în Indese joining we need an Irdexc provider which is an entity that returns the matching rows to given condition. we know Indexing S fôt fast Detriaval of data thus this works quickly.

sole Merge. As name suggests once the Join d table is build it sarts the Columns which appear like equar then then a then a poobe table bas to be solted. After both tables are merged. In this ewe evaluate a join condition for each o with same If it older position. Satisfies then we return such pair as Pair with San Join result so we can say that Nested loop, Index .coop and soit Merge are join evaluation algorithing :: B+ is not evaluation algolithm. pt a) create o kido le 9) All the following DDL commands, Except o select c) drop Bid) Alter on Ans:- ,,DDL stands 681 Data Diseri Definition language, which deals with Schemes and description is of how the data re side in the database. e u In DOL we have commands like Creat ? to create database Alter o alter the structure of database

Drop: to detete the rowslcolumns 31 whole database mancate; to remove all recolds from O the database. Rename : Rename the rowl column are o database above we co say Select it is OML from the is not a command. i Select above we can DDL command 4 ons de as the following rules must by the DBMS to ensure be maintained consistency. ATAU of these b) Referential Integrity que constraints C) Attribute comaind) Entity integrity constraints constraints Ans:- Consistency means A transaction Creates a new and valid state 87 the data, 82, if any failure occurg petung all the data to its state before the transaction. Simply

Consistancy constraints includes it post: 1) domain constraint 2) key constraint 3) Entity Integrity constraint 4) Refertial Integrity Refexe dial Integrity constraint > This constraint as enforced when a foliegn key references the primary key of relation. » It specify that value taken from foregon key must be available in primary key! domin1 Sero Domain constraint les ! domain constraint defines the domain o values of an attribute. ) -> It state value taken by auribute!.is must be atomic Entity Integrity constraint is stilolino → Entity integrity constraint specifies that no atto bute of primary key is a null values if so it violater uniqueness. I can say Database all s So we consistency in ANS AU are ; ensure