Database Design for Freelance Marketplace

Flashcards covering key concepts from a database design lecture focused on a freelance marketplace platform.

Entity-Relationship Model (ER Model)

A conceptual representation of data that outlines entities and their relationships.

Freelancer

A user on the platform who offers services and submits proposals for projects.

Customer

A user who publishes projects on the platform and selects freelancers.

Project

A task published by a customer that freelancers can apply to.

Bid (Proposal)

A submission by a freelancer to work on a project indicating the proposed cost and completion date.

Status of Project

The current state of a project, which can be 'open', 'in progress', or 'completed'.

Review

Feedback provided by the customer after project completion, including a rating and comment.

Primary Key

A unique identifier for a record in a database table.

Foreign Key

A field in one table that uniquely identifies a row of another table.

SQL DDL (Data Definition Language)

Statements used to define the structure of a database, including creating tables and schemas.

Count Aggregate Function

A function that returns the number of items in a group.

HAVING Clause

A clause used to filter groups based on aggregate conditions.

Self-Join

A join where a table is joined with itself to compare rows.

Cardinality

The numerical relationship between entities in a database model.