Answered Questions

  • what is aggregation in DBMS?Explain in simple words.

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    Bapineedu Bollempalli  

    • Member Since Sep-2011 | Sep 18th, 2011


    A concept which is used to model a relationship between a collection of entities and relationships. It is used when we need to express a relationship among relationships. Aggregation - a feature of the entity relationship model that allows a relationship set to participate in another relationship set. This is indicated on an ER diagram by drawing a dashed box around the aggregation.

    Nitin Rathod

    • Apr 14th, 2018

    Aggregation is an abstraction through which relationships are treated as a higher level entities

    Ex :- There exites a ternary relationship teaches between a teacher, department and subject entites, than relationship will be represented as.

    Ajmal Hussain

    • Nov 25th, 2017

    Aggregation of processes, when two entities are treated as a single entities then it is known as aggregation. Here center and courses are acting as a single entitys and then enquires with visi...

  • Database Structure Change

    We already have a database structure, but it is the structure without normalization and very confused and in need of change, but already has a large volume of stored data, for example, all financial data company, which finance department officials are afraid of losing. We are undecided about remodeling the entire structure of the database and retrieve the most basic and all that is possible, or continue...

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    Bapineedu Bollempalli  

    • Member Since Sep-2011 | Sep 18th, 2011


    What ever data base structure you have you can get a Logical model out of it using Reverse Engineering. Erwin is one data model tool which does it. You should apply normalizing techniques to bring the same to a 3NF (Normal Form) and reduce the redundancy. Creating new entities by breaking up of de-normalized entities. Resolving many to many relationships. Finally create a new database structure (Physical Model) based on 3NF from the logical model. Once you acheive a model in 3NF you can do Data migration by simple ETVL ( Extract, Transform, Validation and Load) from old data structure to new data structure. Before doing it your High Level Design should have proper Data mapping document and Metadata document so that you do not lose data.

    Rohit

    • Nov 18th, 2012

    It purely depends what kind of problem you are facing currently. Performance issue can be dealt in n different ways, you need to see the current configuration of DB, the queries, the hardware etc. If ...

  • stored procedures and functions

    what is the difference between functions and stored procedures in sql server? what tool we are using in project management tool for developing packages in ssis? how to rectify the errors in stored procedure in sql server how many ways are there?