Database Partitioning: Principles, Methods, and Features
Database Partitioning Principles
Completeness: Every piece of data in the original table must appear in at least one partition.
Why? This ensures no data is lost during the partitioning process.
Example: If a Customers table is partitioned into regions, all customers must belong to one of the regional partitions.
Reconstruction: It must be possible to reconstruct the original table by combining the partitions.
Why? This ensures that partitioning doesn’t make it impossible to retrieve the full dataset
Read MoreDatabase Concepts and Design Principles
What is a Database?
- A database is a logically organized collection of data with inherent meaning, representing some aspect of the real world and designed for a specific purpose.
- It is designed, built, and populated with data for a specific purpose and has an intended group of users and applications.
Early Databases
- Record-keeping predates computers, with early forms like clay tablets and manual filing systems.
- Computerized file-based systems initially mimicked manual filing systems, storing related data
Database Schema Design: Relational Model Essentials
Conceptual Diagram
Representation of information resources regardless of system users or particular applications and without regard to efficiency issues. It is normally supported by the E/R model.
Logical Schema Global/External
Transformation of the conceptual framework adapted to the data model which supports the DBMS to be used, obtaining a Global Logical Data Schema. The most common is the relational model.
Internal or Physical Schema
Instrumentation as efficiently as possible the logical schema in
Read MoreDatabase Integrity Constraints and Relational Algebra Operations
What are Integrity Constraints?
Integrity constraints are predefined rules used to maintain data quality. They ensure that data insertion, updates, and deletions are performed without affecting data integrity. These constraints act as guidelines, ensuring data accuracy and consistency, thus protecting databases.
Types of Integrity Constraints:
- Domain Constraints
- Not-Null Constraints
- Entity Integrity Constraints
- Key Constraints
- Primary Key Constraints
- Referential Integrity Constraints
Importance of Referential
Read MoreDatabase Management Systems: Keys, Entities, and Normalization
Types of Keys in SQL
In SQL, a key is used to identify a record in a database table. There are several types of keys:
- Primary Key: Uniquely identifies each record in a table. Each table can have only one primary key.
- Foreign Key: A column or a set of columns in one table that refers to the primary key of another table. It is used to establish relationships between tables.
- Candidate Key: A set of attributes that could uniquely identify a record in a table. A table can have multiple candidate keys.
- Alternate
Relational Database Concepts and SQL Fundamentals
Normalization
Normalization is a database design technique used to organize the structure of relational databases. The goal is to reduce data redundancy and improve data integrity by dividing large tables into smaller ones and defining relationships between them. The process involves several normal forms (1NF, 2NF, 3NF, BCNF, etc.), each with its own set of rules:
- 1NF (First Normal Form): Ensures that each column contains atomic values (no repeating groups).
- 2NF (Second Normal Form): Ensures that the