Topic : Architecture

What is a database?


Answer :

- Database offer a single point of mechanism for storing and retrieving information with the help of tables.
- Table is made up of columns and rows where each column stores specific attribute and each row displays a value for the corresponding attribu

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What are the different types of storage systems available and which one is used by Oracle?


Answer :

Two types of storage systems are available
- Relational Database Management System (RDBMS) and Hierarchical Storage Management System (HSM)
- Most databases use RDBMS model; Oracle also uses RDBMS model.
- Hierarchical Storage Management System (HSM)
- Information Management System (IMS) from IBM.
- Integrated Database Management System (IDMS) from CA.

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What are the components of logical data model and list some differences between logical and physical data model?


Answer :

Components of logical data model are
Entity - Entity refers to an object that we use to store information. It has its own table.
Attribute - It represents the information of the entity that we are interested in. It is stored as a column of the table and has specific datatype associated with it.
Record - It refers to a collection of all the properties associated with an entity for one specific condition; represented as row in a table.
Domain - It is the set of all the possible values for a particular attribute.
Relation - Represents a relation between two entities.
Difference between Logical and Physical data model.
- Logical data model represents database in terms of logical objects; such as entities and relationships.
- Physical data model represents database in terms of physical objects; such as tables and constraints.

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What is normalization? What are the different forms of normalization?


Answer :

- Normalization is a process of organizing the fields and tables of a relational database to minimize redundancy and dependency.
- It saves storage space and ensures consistency of our data.
There are six different normal forms
First Normal Fo

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Differentiate between a database and Instance and explain relation between them?


Answer :

- Database is a collection of three important files which include data files; control files and redo log files which physically exist on a disk
- Whereas instance is a combination of oracle background process (SMON; PMON; DBWR; LGWR) and memory struct

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