SQL Join Size Estimator

Overview

SQL Join Size Estimator is a Java-based tool that connects to a SQL database, retrieves table metadata, and estimates join sizes between two user-specified tables. It helps analyze database relationships and assess SQL join efficiency.

Features

• Connects to a SQL database.
• Checks table existence.
• Retrieves table schema.
• Identifies common columns.
• Estimates and computes join size.
• Calculates estimation error.

Prerequisites

• Java 8+
• A SQL database (MySQL, PostgreSQL, etc.)
• JDBC Driver for the chosen database

Installation

1. Clone the repository:

   git clone https://github.com/satwikbhasin/sql-join-size-estimator.git

2. Compile the Java files:

   javac -cp .:path/to/jdbc/driver.jar SQLJoinSizeEstimator.java

3. Run the program:

   java -cp .:path/to/jdbc/driver.jar SQLJoinSizeEstimator

Usage

1. Run the program and enter the names of two database tables.
2. The tool will:
   • Check if the tables exist.
   • Retrieve and display table schema.
   • Identify common columns.
   • Estimate the join size.
   • Compute the actual join size.
   • Display the estimation error.

Example Output

Enter 1st table name: employees
Enter 2nd table name: departments

Table: employees
Columns: id, name, dept_id

Table: departments
Columns: id, dept_name

Common columns: id

Estimated join size: 5000
Actual join size: 4800
Estimation error: 200