It translates DML statements in a query language into low-level instruction that the query evaluation engine can understand.
What is Query evaluation engine ?
It executes low-level instruction generated by compiler.
What is DDL Interpreter ?
It interprets DDL statements and record them in tables containing metadata.
What is Record-at-a-time ?
The Low level or Procedural DML can specify and retrieve each record from a set of records. This retrieve of a record is said to be Record-at-a-time.
What is Set-at-a-time or Set-oriented ?
The High level or Non-procedural DML can specify and retrieve many records in a single DML statement. This retrieve of a record is said to be Set-at-a-time or Set-oriented.
What is Relational Algebra ?
It is procedural query language. It consists of a set of operations that take one or two relations as input and produce a new relation.
What is Relational Calculus ?
It is an applied predicate calculus specifically tailored for relational databases proposed by E.F. Codd. E.g. of languages based on it are DSL ALPHA, QUEL.
How does Tuple-oriented relational calculus differ from domain-oriented relational calculus
The tuple-oriented calculus uses a tuple variables i.e., variable whose only permitted values are tuples of that relation. E.g. QUEL
The domain-oriented calculus has domain variables i.e., variables that range over the underlying domains instead of over relation. E.g. ILL, DEDUCE.
What is normalization ?
It is a process of analysing the given relation schemas based on their Functional Dependencies (FDs) and primary key to achieve the properties
Minimizing insertion, deletion and update anomalies.
What is Functional Dependency ?
A Functional dependency is denoted by X Y between two sets of attributes X and Y that are subsets of R specifies a constraint on the possible tuple that can form a relation state r of R. The constraint is for any two tuples t1 and t2 in r if t1[X] = t2[X] then they have t1[Y] = t2[Y]. This means the value of X component of a tuple uniquely determines the value of component Y.