ERP Data Extractor

Business Case

Problem Statement

ERP data extraction challenges:

• Complex database structures
• Multiple interconnected modules
• Data transformation needs
• Integration with analytics

Solution

Structured extraction and transformation of construction ERP data for analytics, reporting, and cross-system integration.

Technical Implementation

python
import pandas as pd
from typing import Dict, Any, List, Optional
from dataclasses import dataclass, field
from datetime import date, datetime
from enum import Enum
import json


class ERPModule(Enum):
    PROJECT = "project"
    COST = "cost"
    PROCUREMENT = "procurement"
    INVENTORY = "inventory"
    HR = "hr"
    EQUIPMENT = "equipment"
    SUBCONTRACT = "subcontract"
    BILLING = "billing"


@dataclass
class DataSource:
    name: str
    module: ERPModule
    table_name: str
    columns: List[str]
    filters: Dict[str, Any] = field(default_factory=dict)


@dataclass
class ExtractedData:
    source: str
    module: ERPModule
    data: pd.DataFrame
    extracted_at: datetime
    record_count: int


class ERPDataExtractor:
    """Extract and transform data from construction ERP systems."""

    def __init__(self, erp_name: str = "Generic"):
        self.erp_name = erp_name
        self.data_sources: List[DataSource] = []
        self.extracted_data: Dict[str, ExtractedData] = {}
        self._connection = None

    def add_data_source(self, source: DataSource):
        """Add data source for extraction."""
        self.data_sources.append(source)

    def define_project_extraction(self):
        """Define standard project data extraction."""

        self.add_data_source(DataSource(
            name="projects",
            module=ERPModule.PROJECT,
            table_name="projects",
            columns=["id", "code", "name", "status", "start_date", "end_date", "budget", "client_id"]
        ))

        self.add_data_source(DataSource(
            name="project_phases",
            module=ERPModule.PROJECT,
            table_name="project_phases",
            columns=["id", "project_id", "phase_name", "start_date", "end_date", "status"]
        ))

    def define_cost_extraction(self):
        """Define standard cost data extraction."""

        self.add_data_source(DataSource(
            name="cost_items",
            module=ERPModule.COST,
            table_name="cost_items",
            columns=["id", "project_id", "wbs_code", "description", "budgeted", "actual", "committed"]
        ))

        self.add_data_source(DataSource(
            name="cost_transactions",
            module=ERPModule.COST,
            table_name="cost_transactions",
            columns=["id", "project_id", "cost_item_id", "amount", "transaction_date", "type"]
        ))

    def define_procurement_extraction(self):
        """Define procurement data extraction."""

        self.add_data_source(DataSource(
            name="purchase_orders",
            module=ERPModule.PROCUREMENT,
            table_name="purchase_orders",
            columns=["id", "project_id", "vendor_id", "amount", "status", "order_date", "delivery_date"]
        ))

        self.add_data_source(DataSource(
            name="vendors",
            module=ERPModule.PROCUREMENT,
            table_name="vendors",
            columns=["id", "name", "category", "rating", "status"]
        ))

    def extract_from_dataframe(self, source_name: str, df: pd.DataFrame):
        """Extract data from DataFrame (simulating ERP extraction)."""

        source = next((s for s in self.data_sources if s.name == source_name), None)
        if not source:
            return None

        # Apply column selection
        available_cols = [c for c in source.columns if c in df.columns]
        extracted = df[available_cols].copy()

        # Apply filters
        for col, value in source.filters.items():
            if col in extracted.columns:
                extracted = extracted[extracted[col] == value]

        self.extracted_data[source_name] = ExtractedData(
            source=source_name,
            module=source.module,
            data=extracted,
            extracted_at=datetime.now(),
            record_count=len(extracted)
        )

        return self.extracted_data[source_name]

    def transform_data(self, source_name: str,
                       transformations: List[Dict[str, Any]]) -> pd.DataFrame:
        """Apply transformations to extracted data."""

        if source_name not in self.extracted_data:
            return pd.DataFrame()

        df = self.extracted_data[source_name].data.copy()

        for transform in transformations:
            action = transform.get('action')

            if action == 'rename':
                df = df.rename(columns=transform.get('mapping', {}))

            elif action == 'filter':
                col = transform.get('column')
                op = transform.get('operator', '==')
                val = transform.get('value')
                if op == '==':
                    df = df[df[col] == val]
                elif op == '>':
                    df = df[df[col] > val]
                elif op == '<':
                    df = df[df[col] < val]

            elif action == 'calculate':
                new_col = transform.get('new_column')
                formula = transform.get('formula')
                if formula == 'variance':
                    df[new_col] = df[transform['col1']] - df[transform['col2']]

            elif action == 'date_parse':
                col = transform.get('column')
                df[col] = pd.to_datetime(df[col])

        return df

    def join_data(self, left_source: str, right_source: str,
                  left_key: str, right_key: str,
                  join_type: str = "left") -> pd.DataFrame:
        """Join two extracted data sources."""

        if left_source not in self.extracted_data or right_source not in self.extracted_data:
            return pd.DataFrame()

        left_df = self.extracted_data[left_source].data
        right_df = self.extracted_data[right_source].data

        return pd.merge(left_df, right_df, left_on=left_key, right_on=right_key, how=join_type)

    def aggregate_data(self, source_name: str,
                       group_by: List[str],
                       aggregations: Dict[str, str]) -> pd.DataFrame:
        """Aggregate extracted data."""

        if source_name not in self.extracted_data:
            return pd.DataFrame()

        df = self.extracted_data[source_name].data
        return df.groupby(group_by).agg(aggregations).reset_index()

    def get_extraction_summary(self) -> Dict[str, Any]:
        """Get summary of all extractions."""

        summary = {
            'erp_system': self.erp_name,
            'sources_defined': len(self.data_sources),
            'sources_extracted': len(self.extracted_data),
            'total_records': sum(e.record_count for e in self.extracted_data.values()),
            'by_module': {}
        }

        for ext in self.extracted_data.values():
            module = ext.module.value
            if module not in summary['by_module']:
                summary['by_module'][module] = {'sources': 0, 'records': 0}
            summary['by_module'][module]['sources'] += 1
            summary['by_module'][module]['records'] += ext.record_count

        return summary

    def export_to_excel(self, output_path: str) -> str:
        """Export all extracted data to Excel."""

        with pd.ExcelWriter(output_path, engine='openpyxl') as writer:
            # Summary
            summary = self.get_extraction_summary()
            summary_df = pd.DataFrame([{
                'ERP System': summary['erp_system'],
                'Sources Defined': summary['sources_defined'],
                'Sources Extracted': summary['sources_extracted'],
                'Total Records': summary['total_records']
            }])
            summary_df.to_excel(writer, sheet_name='Summary', index=False)

            # Each extracted source
            for name, extracted in self.extracted_data.items():
                sheet_name = name[:31]  # Excel sheet name limit
                extracted.data.to_excel(writer, sheet_name=sheet_name, index=False)

        return output_path

    def export_to_json(self, output_path: str) -> str:
        """Export extracted data to JSON."""

        output = {
            'summary': self.get_extraction_summary(),
            'data': {}
        }

        for name, extracted in self.extracted_data.items():
            output['data'][name] = {
                'module': extracted.module.value,
                'extracted_at': extracted.extracted_at.isoformat(),
                'record_count': extracted.record_count,
                'records': extracted.data.to_dict(orient='records')
            }

        with open(output_path, 'w') as f:
            json.dump(output, f, indent=2, default=str)

        return output_path

    def generate_sql_query(self, source: DataSource) -> str:
        """Generate SQL query for data source."""

        columns = ", ".join(source.columns)
        query = f"SELECT {columns}\nFROM {source.table_name}"

        if source.filters:
            conditions = []
            for col, value in source.filters.items():
                if isinstance(value, str):
                    conditions.append(f"{col} = '{value}'")
                else:
                    conditions.append(f"{col} = {value}")
            query += "\nWHERE " + " AND ".join(conditions)

        return query + ";"

Quick Start

python
# Initialize extractor
extractor = ERPDataExtractor("Procore")

# Define standard extractions
extractor.define_project_extraction()
extractor.define_cost_extraction()

# Simulate extraction from DataFrames
projects_df = pd.DataFrame([
    {"id": 1, "code": "PRJ-001", "name": "Office Building", "status": "Active", "budget": 5000000},
    {"id": 2, "code": "PRJ-002", "name": "Warehouse", "status": "Planning", "budget": 2000000}
])

extractor.extract_from_dataframe("projects", projects_df)

# Get summary
summary = extractor.get_extraction_summary()
print(f"Total records: {summary['total_records']}")

Common Use Cases

1. Transform Data

python
transformed = extractor.transform_data("cost_items", [
    {"action": "rename", "mapping": {"budgeted": "budget", "actual": "spent"}},
    {"action": "calculate", "new_column": "variance", "formula": "variance", "col1": "budget", "col2": "spent"}
])

2. Join Sources

python
joined = extractor.join_data("cost_items", "projects", "project_id", "id")

3. Aggregate

python
by_project = extractor.aggregate_data("cost_items", ["project_id"], {"budgeted": "sum", "actual": "sum"})

Resources

• DDC Book: Chapter 3.4 - Construction ERP Systems
• Website: https://datadrivenconstruction.io