Code Editor for app.py

import streamlit as st
import pandas as pd
from sqlalchemy import create_engine, inspect

st.title("SQL Schema Explorer")

# Input for connection string
connection_string = st.text_input(
    "Enter SQLAlchemy connection string:",
    value="sqlite:///example.db",
    help="Example: sqlite:///database.db, postgresql://user:password@localhost:5432/dbname"
)

if connection_string:
    try:
        # Create engine
        engine = create_engine(connection_string)
        
        # Get inspector
        inspector = inspect(engine)
        
        # Get all table names
        tables = inspector.get_table_names()
        
        if not tables:
            st.warning("No tables found in the database.")
        else:
            st.success(f"Found {len(tables)} tables in the database.")
            
            # Select table to inspect
            selected_table = st.selectbox("Select a table to inspect:", tables)
            
            if selected_table:
                # Get columns information
                columns = inspector.get_columns(selected_table)
                
                # Create DataFrame for columns
                df_columns = pd.DataFrame([{
                    'Column Name': col['name'],
                    'Type': str(col['type']),
                    'Nullable': col.get('nullable', True),
                    'Primary Key': col.get('primary_key', False),
                    'Default': str(col.get('default', ''))
                } for col in columns])
                
                st.subheader(f"Schema for table: {selected_table}")
                st.table(df_columns)
                
                # Get foreign keys
                fks = inspector.get_foreign_keys(selected_table)
                if fks:
                    st.subheader("Foreign Keys:")
                    for fk in fks:
                        st.write(f"- {', '.join(fk['constrained_columns'])} -> "
                                f"{fk['referred_table']}.{', '.join(fk['referred_columns'])}")
                
                # Get indexes
                indexes = inspector.get_indexes(selected_table)
                if indexes:
                    st.subheader("Indexes:")
                    for idx in indexes:
                        st.write(f"- {idx['name']}: columns={', '.join(idx['column_names'])} "
                                f"(unique={idx['unique']})")
                
                # Sample data preview
                st.subheader("Sample Data Preview")
                try:
                    sample_query = f"SELECT * FROM {selected_table} LIMIT 5"
                    sample_data = pd.read_sql(sample_query, engine)
                    st.dataframe(sample_data)
                except Exception as e:
                    st.error(f"Could not fetch sample data: {str(e)}")
                
    except Exception as e:
        st.error(f"Error connecting to database: {str(e)}")