ERD is a diagram that displays the relationship of entity sets stored in a database. In other words, ER diagrams help to explain the logical structure of databases. ER diagrams are created based on three basic concepts: entities, attributes and relationships.
ER Diagrams contain different symbols that use rectangles to represent entities, ovals to define attributes and diamond shapes to represent relationships.
R diagram looks very similar to the flowchart. However, ER Diagram includes many specialized symbols, and its meanings make this model unique. The purpose of ER Diagram is to represent the entity framework infrastructure.
ER Model
ER Model stands for Entity Relationship Model is a high-level conceptual data model diagram. ER model helps to systematically analyses data requirements to produce a well-designed database. The ER Model represents real-world entities and the relationships between them. Creating an ER Model in DBMS is considered as a best practice before implementing your database.
ER Diagram Symbol
Rectangles: This Entity Relationship Diagram symbol represents entity types
Ellipses : Symbol represent attributes
Diamonds: This symbol represents relationship types
Lines: It links attributes to entity types and entity types with other relationship types
CSS stands for Cascading Style Sheets.css describes how html elements are to be displayed on screen, paper, or in other media.Css saves a lot of work. It can control the layout of multiple web pages all at once.
Css has 3 types
1.Inline:-Add a style line by Line(directly in html)
2.Internal:-Add style in body
3.External:-Linking external css file
Css Syntax
ex:-p {
text-align: center;}
p is a selector
text-alignis a property, andcenteris the property value
Css selectors
CSS selectors are used to "find" the HTML elements you want to style.
Simple selectors:-
Selects HTML elements based on the element name
The id attribute of an HTML element to select a specific element.
Combinator selectors
(select elements based on a specific relationship between them)
class selectors(select elements based on a certain state)
The id selector uses the id attribute of an HTML element to select a specific element.
Pseudo element selectors (select and style a part of an element)
html tags selected by html element
Attribute selector(select elements based on an attribute or attribute value)
The Attribute selector uses the attribute of an HTML element to select a specific element.