by Data
- Data is a collections of similar type of raw fact
Example
- User Information
Meta Data
- Data About Data is called Meta Data
Database
- Database is a collection of tables
- यह Secondary Memory में store किया जाता है
Schema
- Logical Design of Database
DBMS | Database Management System
- यह एक सोफ्टवेयर होता है जो यूजर और डेटाबेस के बीच माध्यम (Interface) बनाता है
- DBMS is an Interface Between User and Database
- DBMS is an Application Software
User ⇔ DBMS ⇔ Database
Model of DBMS
- (HDBMS) ⇒ Hierarchical Database Management System
- (NDBMS) ⇒ Network Database Management System
- (DDBMS) ⇒ Distributed Database Management System
- (RDBMS) ⇒ Relational Database Management System
- (OODBMS) ⇒ Object Orientated Database Management System
RDBMS
- its Stands Form Relational Database Management System
- it is Collection of Table
Database Table | Relation
- Database Table is a collection of records
- Database Table is a collection of rows and Columns that contains relational data
- Every Table is an Relation or Every Relation is Table
Example
Student(S_ID, S_Name, S_Age) ⇒ Implicit Notation
| S_ID | S_Name | S_Age |
|---|---|---|
| 1001 | Vikas | 21 |
| 1002 | Aman | 23 |
| 1003 | Seema | 20 |
| 1004 | Ritu | 22 |
| 1005 | Rohit | 24 |
Explicit Notation
Record | Row | Tuple | Entity
- Collection of Fields
Cardinality
Cardinality of Table
- Number of Records in the table
- Number of Row in the table
- Number of Tuples in the table
- Total Records
Field | Column | Attribute
Arity | Degree
Degree of Relation
- Number of Attribute in Relation
- Number of Column in Relation
- Number of Field in Relation
DBMS Software
- SQL
- MySQL
- MS Access
- IBM DB2
Instance
- Particular Point of Data is Called Instance
Architecture of Database System
- there are Three Type of Layer
- External Layer (View Layer)
- Conceptual Layer (Logical Layer)
- Physical Layer (Database )
ACID Property
- Atomicity
- Consistency
- Isolation
- Durability
Type of Keys | Keys Concept
- Super Key
- Candidate Key
- Primary Key
- Alternate Key | Secondary Key
- Foreign Key
- Composite Key
Super Key
- set of Attribute that are Uniquely identify each and Every record in a relation
- one or more Attribute
- minimum one Candidate Key
Candidate Key
- Candidate Key is a Subset of Super Key
- Set of Minimal Attributes that are Uniquely Identified each and every Tuple
Primary Key
- Uniquely identify a record
- Primary Key always Unique and Not Null
- only one Primary Key in a Table
Foreign Key
- Reference Key
- Connect a another Table
- An Attribute of the table matching the Primary key of another table, is called Foreign Key
Composite Key
- दो या दो से अधिक Attribute से मिलकर बनने वाली key को Composite key कहते है
Alternate Key | Secondary Key
- Alternate Key is knows as Secondary Key
- Primary Key को छोड़ कर सभी key Alternate Key होती है
- Alternate Key = Candidate Key – Primary Key
Data Dictionary
- Field Name, Field Type, Field Format
ER Diagram
- Entity Relationship Diagram
- its is High Level Data Tools
- it is Graphical Design of Database
Weak Entity Set
- Double Rectangle Box
Rectangle Box
- Entity set Represented by Rectangle Box
Ellipse Box
- Attributes Represented by Ellipse Box
Diamonds Box
- Relationship Represented by Diamonds Box
SQL
Database | डेटाबेस
create database school ↵ Create a Database
use school ↵ Use Database
Table | टेबल
Syntax
create table table_name
(
column1 datatype,
column2 datatype,
column3 datatype,
column4 datatype,
column5 datatype
);
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