1. Short note: database, data, application, metadata, RDBMAS, data integrity.
Database: A collection of information, preferably related information, and preferably organized.
Data: A term applier to organized information.
Application: A front end tool used by developers, in-house staff, and-users to access a database.
Metadata: data is the data about the data.
RDBMS: Relational database management system.
Data integrity: The validity of data is called Data integrity.
2. Name the different type database.
Ans: Three type of database are available.
1. Transactional.
2. Decision support system (DSS).
3. Hybrid.
3. What do you mean by transitional database?
Ans: A transactional database is a based on small change to the database. Two types database are Client server database & OLTP database.
4. What is database modeling? Write down the different database model techniques?
Ans: A model used to organized and apply structure to other disorganized information.
The different database model techniques are 1. File system 2.Hierarchical 3.Network 4.Relational 5.Object 6. Object-Relational
4. What are the methods you have to follow to design a database?
1. Requirement analysis.
2. Conceptual design
3. Logical design
4. Physical design
5. Tuning phase
5.What are business rules? Write down the aspects of business rule.
Business rule: business rules for an organization are the process & flows whatever is involved in daily working activities of that organization.
Aspects of business rules are:
1.any types of organization policies.
2.any types of calculation or formula.
3.any types of regulation.
6.What is data type? Write down the sections of data type.
Data type: Data type restrict the values in the fields.
Sections of data types are :1.simple data type , 2.complex data type,3.spealized data type.
7.What is constraints? Give some examples
Constraint: Constraints restricts the values that are allowed in the table fields.
Some of examples of constrains are Not null, validation check , keys.
8. Shortly brief the key constrain.
Key constraint: Key constraints include the primary keys ,foreign keys ,unique keys .Key constraints allow the checking and validation of values between the fields in different tables. Primary keys and foreign keys are used in relationships between the parent tables and child tables.
9.What is normalization? Write down its benefits.
Normalization : Normalization removes the duplication of data minimize the chunk of redundant
Benefits of normalization:
(1).physical space is reduced
(2).Data becomes best organized .
(3).A single table record is updated.
10.What are difference between primary key & unique key?
Ans: primary keys:- A primary key is used to uniquely identify a record in a table .A primary key doesn’t allow duplicate & null value.
Unique keys:- A unique key is created on a field containing only unique values trough out an entire table. Unique keys allows null value.
11.Shortly brief : view, index, PK ,UK & FK.
Ans:view :-A logical overlay containing a query , executed whenever the view is accessed . Repeated query execution can make views very inefficient in busy environment.
Index:- An index is usually a copy of a very small section of table , such as a single field & short length field.
PK:- A primary key is used to uniquely identify a record in a table .A primary key doesn’t allow duplicate & null value.
UK:- A unique key is created on a field containing only unique values trough out an entire table. Unique keys allows null value.
FK:- A foreign key define the reference for each record in the child table , referencing back the primary key in the parents table.
12.What do mean by functional dependency?
Functional dependence: “Y” is functionally dependent on ” X” if the value of “Y” is determined by “X”. in other words if Y=X+1, the value of “X” resultant value of “Y”
13.What is SQL?
Ans: SQL means that structure Query Language. It used to access data in a relational database.
Write down the different types of Query Commands and change commands.
14.Write down different types of query commands & data changes commands.
Query commands:- 1.Basic query 2. Filtered query 3. Sorted query 4. Aggregated query 4. Join query 5. Nested query 6. Composite query
Data change commands:- Insert, Update, Delete
15.Define shortly : Nested quire, composite query.
Nested quire: A nested query is also know as a sub query, which is a query contained within another query.
Composite query: A composite query is a query that merges multiple query results together, most often using the UNION keyword.
16.Define shortly: Inner join, Cross join, Outer join and self join?
Inner join: An intersection between two table using matching field values. Retuning records common to both tables only.
Cross join: This is also known mathematically as a Cartesian product. A cross join merges all records in one table with all records in another table, regardless of any matching values.
Outer join: An intersection plus rows outside the intersection, in one table and not in the other table of a join.
self join: A self join simply joins a table to itself, and is commonly used with a table containing a hierarchy of records.
17. Write down the demoralization Tricks?
Ans: – demoralization Tricks are :
1. Separate active and inactive data.
2. Copy fields between tables.
3. Summary fields in parent tables.
4. Separate heavily and lightly accessed fields.
18. What is a star schema?
Ans: The most effective approach for a data warehouse database model is called a star schema.
19. What is a snowflake schema?
Ans: A data warehouse, single fact table structure with dimension tables in multiple layered hierarchies of dimensional tables.
20. What are fact table and Dimension table?
Fact table: A term generally applying to an unstructured file, such as a text file.
Dimension table: A descriptive or static data table in a data warehouse.
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