DBS

DBS

1. DBMS

   • Short for: Databank Management System
   • Key Features
     • Integrated Data Management
       • It. . .  - centralizes and unifies data storage for consistency and efficiency. - supports the creation of relationships between data elements. - Allows for controlled redundancy to improve performance where needed
     • Database Languages
       • Interface Tool for Database
       • Retrieval
         • Querying data efficiently.
       • Manipulation (DML)
         • CRUD (create, read, update delete) using DML
       • Management (DDL)
         • OR: Definition Structuring the database schema with DDL.
       • Authorisation (DCL)
         • Managing permissions and security with DCL.
     • Data Dictionary
       • A repository of metadata (data about data) describing database structure, tables, and relationships.
     • Consistency Control
       • - Enforces integrity rules to maintain correct data states. - Protects against invalid changes to both logical and physical data.
     • Access Control
       • Secures data through authorization rules, ensuring only permitted users can view or modify sensitive data.
     • Transactions
       • Bundles multiple operations into atomic units (Atomicity) All succeed or all fail together, ensuring reliability and consistency.
     • Concurrency Control
       • Manages simultaneous user access to prevent conflicts: Examples include resolving write conflicts or maintaining isolation for data updates.
     • Recovery
       • Restores the database to a valid state after hardware or software failures using recovery mechanisms.
     • Views
       • Provides customized "views" of data tailored to specific user roles or application needs. It is Defined by the database's external schema
   • Advantages
     • Standardization
       • Implements uniform formats for data and processes, simplifying management and collaboration.
     • Efficient Datamanagement
       • Leverages indexing and optimized storage strategies to handle large datasets swiftly.
     • Reduced Dev Time
       • Developers can focus on application logic, as common database features are pre-implemented.
     • Flexibility
       • Easily adapts to changes in data requirements without rewriting existing code.
     • Availability
       • Supports multi-user access with immediate visibility of changes post-transaction.
     • Cost Effectiveness
       • Centralization allows for investment in high-performance systems, lowering overall operational costs.
   • Disadvantages
     • High Initial Cost
       • Expensive hardware and software acquisition costs.
     • High Skill Level
       • Needs trained personnel like database designers and administrators.
     • Centralization Risks
       • Single points of failure may impact the entire system if not mitigated (e.g., backups, failover systems).
     • Potentially Overkill
       • Overhead may not justify the use of a DBMS for simple, static data storage needs.

2. Top 10

   • Oracle
   • MYSQL
   • Microsoft SQL Server
   • PostgreSQL
   • MongoDB
   • Redis
   • Snowflake
   • Elasticsearch
   • IBM Db2
   • SQLite

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