Operational Data Store Interview Questions & Answers

  1. Question 1. When Is A Functional Dependency F Said To Be Minimal?

    Answer :

    • 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.
  2. Question 2. What Is Operational Data Store?

    Answer :

    An operational data store (or “ODS”) is a database designed to integrate data from multiple sources to make analysis and reporting easier.

  3. Data Warehouse ETL Toolkit Interview Questions

  4. Question 3. What Is Multivalued Dependency?

    Answer :

    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)) ]

  5. Question 4. What Is Ddl (data Definition Language)?

    Answer :

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

  6. Data Warehouse ETL Toolkit Tutorial

  7. Question 5. What Is Vdl (view Definition Language)?

    Answer :

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

  8. Data Warehousing Interview Questions

  9. Question 6. What Is Degree Of A Relation?

    Answer :

    It is the number of attribute of its relation schema.

  10. Question 7. What Is A Relation Schema And A Relation?

    Answer :

    A relation Schema denoted by R(A1, A2, ?, An) is made up of the relation name R and the list of attributes Ai that it contains. A relation is defined as a set of tuples. Let r be the relation which contains set tuples (t1, t2, t3, …, tn). Each tuple is an ordered list of n-values t=(v1,v2, …, vn).

  11. Data Warehousing Tutorial
    Data Center Management Interview Questions

  12. Question 8. How Does Tuple-oriented Relational Calculus Differ From Domain-oriented Relational Calculus?

    Answer :

    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.

  13. Question 9. What Is Relationship?

    Answer :

    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.

  14. Data Stage Interview Questions

  15. Question 10. What Is Normalization?

    Answer :

    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.
  16. Data Structure & Algorithms Tutorial

  17. Question 11. What Is Functional Dependency?

    Answer :

    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.

  18. Data analyst Interview Questions