RDBMS

The domain of attribute must include only atomic (simple, indivisible) values.

It guarantees that the spurious tuple generation does not occur with respect to relation schemas after decomposition.

Multivalued dependency denoted by X-->Y specified on relation schema R, where X and Y are both subsets of R, specifies the following constraint on any relation r of R: if two tuples t1 and t2 exist in r such that t1[X] = t2[X] then t3 and t4 should also exist in r with the following properties

► t3[x] = t4[X] = t1[X] = t2[X]

► t3[Y] = t1[Y] and t4[Y] = t2[Y]

► t3[Z] = t2[Z] and t4[Z] = t1[Z]

where [Z = (R-(X U Y)) ]

It executes low-level instruction generated by compiler.

► Every dependency in F has a single attribute for its right hand side.

► It cannot replace any dependency X -->A in F with a dependency Y--> A where Y is a proper subset of X and still have a set of dependency that is equivalent to F.

► We cannot remove any dependency from F and still have set of dependency that is equivalent to F.

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.

It is a process of analysing the given relation schemas based on their Functional Dependencies (FDs) and primary key to achieve the properties

► Minimizing redundancy

► Minimizing insertion, deletion and update anomalies.

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.

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.

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.

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.

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.

It interprets DDL statements and record them in tables containing metadata.

The storage structures and access methods used by database system are specified by a set of definition in a special type of DDL called data storage-definition language.

This language is to specify the internal schema. This language may specify the mapping between two schemas.

A data base schema is specifies by a set of definitions expressed by a special language called DDL.

It is an association among two or more entities.

Relationship Set - The collection (or set) of similar relationships.

Relationship Type - Relationship type defines a set of associations or a relationship set among a given set of entity types.

Degree of Relationship Type - It is the number of entity type participating.

It translates DML statements in a query language into low-level instruction that the query evaluation engine can understand.

It specifies user views and their mappings to the conceptual schema.

It is the number of attribute of its relation schema.