Bash Shell Script Database Management System (DBMS)

Project Overview

This project develops a lightweight, file-based Database Management System (DBMS) using Bash scripting, stores data on the hard disk as text files, with each database represented as a directory containing table files in a CSV format. Performing basic database operations through simple CLI and workflow.

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Project Features (Main Menu)

The CLI menu provides the following options:

1. Create Database: Create a new database.
2. List Databases: Display all available databases.
3. Connect to Databases: Select/use a specific database.
4. Drop Database: Delete a specific database and its contents.

When connected to a database, a sub-menu allows table-level operations (create table, list tables, insert record, query data, delete table, etc).

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Project Decomposition

The project is broken into 5 components for modularity and clarity. Each component is responsible for specific functionality, implemented as separate Bash scripts or functions that interact through function calls and file system operations.

1. Main CLI: Provides the menu interface and orchestrates all operations.
2. Database Management: Handles creation, listing, and deletion of databases.
3. Data Storage: Manages the physical storage of databases and tables on disk.
4. Table and Record Operations: Manages tables and records within a selected database (sub-menu operations).
5. Query: For retrieving data from tables with basic filtering.

Component Structure

The Main CLI is the entry point (orchestrator) that calling other modules. Modules interact with the file system via the Data Storage Module.

+-------------------+
|   Main CLI Module |
|   (dbms.sh)       |
|   Menu Loop       |
|   Parses Input    |
+-------------------+
         |
         | Calls Functions
         v
+-----------------------------------+
| Database Management Module        |
| - Create Database                 |
| - List Databases                  |
| - Drop Database                   |
| - Connect to Database (Sub-menu)  |
+-----------------------------------+
         |                          |
         | Uses                     | Connects to Sub-menu
         v                          v
+-------------------+       +-------------------+
| Data Storage      |       | Table & Record    |
| Module            |<----->| Operations Module |
| - File I/O        |       | - Create Table    |
| - Directory Mgmt  |       | - Insert/Update   |
| - CSV Parsing     |       | - Delete Record   |
+-------------------+       +-------------------+
                            | Uses
                            v
                           +-------------------+
                           | Query Module      |
                           | - Select All      |
                           | - Select Where    |
                           | - Format Output   |
                           +-------------------+

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Directory Structure

dbms_project/
├── dbms.sh                   # Entry-point script
├── modules/
│   ├── data_storage.sh       # Data storage module
│   ├── database_ops.sh       # Database management module
│   ├── table_ops.sh          # Table and record operations module
│   ├── query_ops.sh          # Query module
└── DATA/                     # Database storage directory