BI Builder

BI Builder

Build BI dashboards from existing databases, from data exploration to full implementation.

Tech Stack

Core Workflow

Database Connection → Schema Exploration → Requirements Dialog → Metrics Design → Chart Planning → Page Implementation

Workflow Flexibility

Skip phases based on project state and user needs:

Decision criteria:

• Check if prisma/​schema.prisma exists in project
• Ask user "Do you have specific metrics requirements?"
• Ask user "Do you need a full dashboard or just a single chart?"

---

Phase 1: Database Connection

1.1 Check and Install Prisma

First, check if Prisma is already installed in the project:

# Check if prisma is in package.json dependencies
grep -q '"prisma"' package.json && echo "Prisma installed" || echo "Prisma not installed"

If Prisma is not installed, install it:

# Install Prisma as dev dependency
npm install prisma --save-dev

# Install Prisma Client
npm install @prisma/​client

1.2 Initialize Prisma

# Initialize Prisma (creates prisma/​schema.prisma and .env)
npx prisma init

Note: If prisma/​schema.prisma already exists, skip this step.

1.3 Create .env with Placeholders

⚠️ Security Note: Never ask users to share database credentials directly.

First, ask user which database type they use, then create .env file with placeholders:

Which database are you using?
1. MySQL
2. PostgreSQL
3. Supabase
4. SQLite

For MySQL:

# Database Connection
# Please fill in your database credentials below
DATABASE_URL="mysql://YOUR_USERNAME:YOUR_PASSWORD@YOUR_HOST:3306/​YOUR_DATABASE"

# Example:
# DATABASE_URL="mysql://root:password123@localhost:3306/​myapp_db"

For PostgreSQL:

# Database Connection
# Please fill in your database credentials below
DATABASE_URL="postgresql://YOUR_USERNAME:YOUR_PASSWORD@YOUR_HOST:5432/​YOUR_DATABASE"

# Example:
# DATABASE_URL="postgresql://postgres:password123@localhost:5432/​myapp_db"

For Supabase:

# Supabase Database Connection
# Find your connection string in: Supabase Dashboard → Project Settings → Database → Connection string → URI
DATABASE_URL="postgresql://postgres.YOUR_PROJECT_REF:YOUR_PASSWORD@aws-0-YOUR_REGION.pooler.supabase.com:6543/​postgres?pgbouncer=true"

# Direct connection (for migrations)
DIRECT_URL="postgresql://postgres.YOUR_PROJECT_REF:YOUR_PASSWORD@aws-0-YOUR_REGION.pooler.supabase.com:5432/​postgres"

# Example:
# DATABASE_URL="postgresql://postgres.abcdefghijkl:[email protected]:6543/​postgres?pgbouncer=true"

For SQLite:

# Database Connection
DATABASE_URL="file:./​dev.db"

After creating the file, tell the user:

For MySQL/​PostgreSQL:

I've created .env file with placeholders. Please fill in your actual database credentials:
- YOUR_USERNAME → your database username
- YOUR_PASSWORD → your database password
- YOUR_HOST → database host (e.g., localhost or IP address)
- YOUR_DATABASE → database name

Tip: Use a read-only account for safety.

Let me know when you've filled in the credentials.

For Supabase:

I've created .env file with Supabase placeholders. To get your connection string:

1. Go to Supabase Dashboard → Your Project
2. Click "Project Settings" (gear icon)
3. Go to "Database" section
4. Copy the "Connection string" → "URI" format
5. Replace [YOUR-PASSWORD] with your database password

Let me know when you've filled in the credentials.

1.4 Configure Prisma Schema

After user confirms .env is configured, update prisma/​schema.prisma:

For MySQL/​PostgreSQL/​SQLite:

generator client {
  provider = "prisma-client-js"
}

datasource db {
  provider = "mysql"  // or postgresql, sqlite
  url      = env("DATABASE_URL")
}

For Supabase (requires directUrl for migrations):

generator client {
  provider = "prisma-client-js"
}

datasource db {
  provider  = "postgresql"
  url       = env("DATABASE_URL")
  directUrl = env("DIRECT_URL")
}

1.5 Pull Database Schema

# Pull schema from existing database
npx prisma db pull

# Generate Prisma Client
npx prisma generate

1.6 Error Handling

When connection fails:

Post-schema pull checks:

• If few tables (< 3) → Confirm connection to correct database
• If no relationships → May be legacy database, need manual relationship analysis

---

Phase 2: Schema Exploration & Analysis

2.1 Read Generated Schema

After prisma db pull, read prisma/​schema.prisma and analyze:

• Table structure: What tables exist, what fields each has
• Data types: Numeric, datetime, categorical fields
• Relationships: Table associations (one-to-many, many-to-many)
• Indexes: Which fields are indexed, indicating common query dimensions

2.2 Identify Metric Potential

Identify buildable metrics by field type:

2.3 Generate Data Overview Report

Present database overview to user:

## Database Overview

### Core Tables
- **orders** (Orders table): 12 fields, related to users, products
- **users** (Users table): 8 fields
- **products** (Products table): 10 fields, related to categories

### Available Metrics
**Transaction Metrics**
- Total revenue (orders.total)
- Order count (orders.count)
- Average order value (orders.total / orders.count)

**User Metrics**
- Total users (users.count)
- New users (users.created_at)

**Product Metrics**
- Sales ranking (order_items.quantity)
- Category distribution (categories)

### Time Dimensions
- orders.created_at → Supports daily/​weekly/​monthly analysis
- users.created_at → Supports user growth analysis

---

Phase 3: Requirements Dialog

3.1 Questioning Strategy

Principle: Ask one question at a time, prefer multiple choice, ask in rounds.

Round 1: Industry Identification (Highest Priority)

Question 0: What industry is your business in?
Options: E-commerce/​Retail / SaaS Software / Financial Services / Content/​Media / Education / Healthcare / Logistics/​Supply Chain / Other

Industry determines metric direction:

Round 2: Core Metrics Confirmation (Use AskUserQuestion tool)

Based on industry + schema analysis, generate metric options:

Question 1: Based on [industry] context and database analysis, which core metrics matter most to you? (Multiple select)
Options: [Combine industry typical metrics + schema-supported metrics]

Question 2: What's your primary time granularity for analysis?
Options: Daily / Weekly / Monthly / Quarterly

Round 3: Conditional Follow-ups

Only ask when conditions are met:

Round 4: Confirmation

Show requirements confirmation template, ask "Is the above understanding correct?"

3.2 Data Structure Limitation Handling

When user requirements don't match data, clearly inform:

3.3 Requirements Confirmation Template

Organize user requirements:

## Requirements Confirmation

### Dashboard Name
Sales Analytics Dashboard

### Core Metrics (KPI Cards)
1. Total Revenue - orders.total sum
2. Order Count - orders count
3. AOV - Total Revenue / Order Count
4. New Users - users count (this month)

### Chart Requirements
| Chart | Type | Data Source | Dimension |
|-------|------|-------------|-----------|
| Revenue Trend | Line Chart | orders.total | By day/​month |
| Category Sales | Pie Chart | categories | Category distribution |
| Top 10 Products | Bar Chart | products | Sales ranking |
| Order Status | Pie Chart | orders.status | Status distribution |

### Filters
- Date range picker
- Product category dropdown
- Order status multi-select

### Other Requirements
- CSV export support
- Responsive layout

---

Phase 4: Metrics Design

4.1 Define Metric Calculation Logic

Based on confirmed requirements, define calculation for each metric:

// lib/​metrics.ts

// KPI Metrics
export async function getKPIs(startDate: Date, endDate: Date) {
  const [revenue, orders, users] = await Promise.all([
    // Total revenue
    prisma.order.aggregate({
      where: { createdAt: { gte: startDate, lte: endDate }, status: { not: 'CANCELLED' } },
      _sum: { total: true },
    }),
    // Order count
    prisma.order.count({
      where: { createdAt: { gte: startDate, lte: endDate }, status: { not: 'CANCELLED' } },
    }),
    // New users
    prisma.user.count({
      where: { createdAt: { gte: startDate, lte: endDate } },
    }),
  ]);

  return {
    revenue: Number(revenue._sum.total) || 0,
    orders,
    avgOrderValue: orders > 0 ? Number(revenue._sum.total) / orders : 0,
    newUsers: users,
  };
}

4.2 Time Series Metrics

// Aggregate by time granularity
export async function getRevenueTrend(
  startDate: Date,
  endDate: Date,
  granularity: 'day' | 'week' | 'month'
) {
  const format = {
    day: '%Y-%m-%d',
    week: '%Y-%u',
    month: '%Y-%m',
  }[granularity];

  return prisma.$queryRaw`
    SELECT
      DATE_FORMAT(created_at, ${format}) as period,
      SUM(total) as revenue,
      COUNT(*) as orders
    FROM orders
    WHERE created_at BETWEEN ${startDate} AND ${endDate}
      AND status != 'CANCELLED'
    GROUP BY period
    ORDER BY period
  `;
}

4.3 Grouped Metrics

// Category distribution
export async function getCategoryDistribution(startDate: Date, endDate: Date) {
  return prisma.$queryRaw`
    SELECT
      c.name as category,
      SUM(oi.quantity * oi.price) as revenue,
      SUM(oi.quantity) as quantity
    FROM order_items oi
    JOIN products p ON oi.product_id = p.id
    JOIN categories c ON p.category_id = c.id
    JOIN orders o ON oi.order_id = o.id
    WHERE o.created_at BETWEEN ${startDate} AND ${endDate}
      AND o.status != 'CANCELLED'
    GROUP BY c.id, c.name
    ORDER BY revenue DESC
  `;
}

Before writing complex queries → Must read data-layer.md#data-aggregation-queries

---

Phase 5: Chart Planning

5.1 Visualization Type Selection

5.2 Layout Type Selection

Ask user about their dashboard purpose to recommend a layout:

What is the primary purpose of this dashboard?
1. Executive Overview - High-level KPIs for quick decision-making
2. Operations Monitoring - Real-time data and alerts
3. Deep Analysis - Multi-dimensional filtering and exploration
4. Period Comparison - YoY/​MoM comparison and benchmarking

Before implementing layout → Must read dashboard-patterns.md#common-bi-layout-patterns

5.3 Layout Structure

Default Executive Dashboard layout:

┌─────────────────────────────────────────────────────────┐
│ Filter Bar: [Date Range] [Category] [Status] [Apply]    │
├─────────┬─────────┬─────────┬───────────────────────────┤
│ KPI 1   │ KPI 2   │ KPI 3   │ KPI 4                     │
│ Revenue │ Orders  │ AOV     │ New Users                 │
├─────────────────────────────┬───────────────────────────┤
│                             │                           │
│   Revenue Trend (Line)      │   Category Dist (Pie)     │
│   lg:col-span-2             │                           │
│                             │                           │
├─────────────────────────────┴───────────────────────────┤
│                                                         │
│              Top 10 Products (Bar Chart)                │
│                                                         │
├─────────────────────────────────────────────────────────┤
│              Order Details (DataTable)                  │
└─────────────────────────────────────────────────────────┘

---

Phase 6: Page Implementation

6.1 Directory Structure

app/​dashboard/
├── page.tsx              # Main page
├── loading.tsx           # Loading skeleton
└── components/
    ├── kpi-cards.tsx         # KPI cards
    ├── revenue-chart.tsx     # Revenue trend chart
    ├── category-pie.tsx      # Category pie chart
    ├── top-products.tsx      # Product ranking
    ├── data-table.tsx        # Reusable DataTable component
    ├── columns.tsx           # Table column definitions
    ├── filters.tsx           # Filters
    └── export-button.tsx     # Export button

lib/
├── prisma.ts             # Prisma client
└── metrics.ts            # Metric calculation functions

app/​api/​dashboard/
├── route.ts              # Combined data API
├── kpi/​route.ts          # KPI API
├── revenue/​route.ts      # Revenue trend API
└── categories/​route.ts   # Category data API

6.2 Implementation Order

1. Prisma client → lib/​prisma.ts
2. Metric functions → lib/​metrics.ts
3. API routes → app/​api/​dashboard/
4. KPI cards → Simplest, verify data flow first
5. Chart components → Implement one by one
6. Filters → Add interactivity
7. Export functionality → Complete last

6.3 Component Implementation

Chart components must use "use client" and ResponsiveContainer:

"use client";

import { ResponsiveContainer, LineChart, Line, XAxis, YAxis, Tooltip } from "recharts";

export function RevenueChart({ data }: { data: { period: string; revenue: number }[] }) {
  return (
    <ResponsiveContainer width="100%" height={300}>
      <LineChart data={data}>
        <XAxis dataKey="period" />
        <YAxis />
        <Tooltip />
        <Line type="monotone" dataKey="revenue" stroke="hsl(var(--primary))" />
      </​LineChart>
    </​ResponsiveContainer>
  );
}

Before creating chart components → Must read recharts-guide.md for the corresponding chart type

Before creating DataTable components → Must read table-patterns.md

Before implementing page layout → Must read dashboard-patterns.md

Before implementing export functionality → Must read export-patterns.md

---

Quick Reference

Prisma Commands

npx prisma db pull      # Pull schema from database
npx prisma generate     # Generate Prisma Client
npx prisma studio       # Open database management UI

Chart Color Scheme

const CHART_COLORS = [
  "hsl(221, 83%, 53%)",  // blue
  "hsl(142, 71%, 45%)",  // green
  "hsl(38, 92%, 50%)",   // amber
  "hsl(0, 84%, 60%)",    // red
  "hsl(262, 83%, 58%)",  // purple
];

Responsive Breakpoints

// KPI row
<div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-4 gap-4">

// Main chart area
<div className="grid grid-cols-1 lg:grid-cols-3 gap-4">
  <div className="lg:col-span-2">{/​* Large chart */​}</​div>
  <div>{/​* Small chart */​}</​div>
</​div>

Reference Document Usage Rules

⚠️ Do not read all documents upfront. Only load on-demand when entering the corresponding phase.

Required Reading Triggers

Document Index

• data-layer.md - Prisma queries, Schema analysis, API design
• recharts-guide.md - Chart code examples by type
• table-patterns.md - DataTable with sorting, filtering, pagination
• dashboard-patterns.md - Page layouts, KPI cards, filters
• export-patterns.md - CSV export, image export