Creating an Enterprise ETL tool

To create an enterprise application for scanning Oracle databases and generating a profile of columns, sizing, and metadata, the baseline codebase should focus on database connectivity, metadata extraction, and report generation. Here’s a step-by-step guide and recommendations for your baseline:


1. Baseline Tech Stack


Language and Framework


• Python (widely used for database interaction and metadata profiling).

• Framework: Flask/FastAPI for a lightweight web service, or Django for a more full-fledged enterprise app.


Database Connectivity


• cx_Oracle: Oracle’s Python library for connecting to Oracle databases.

• SQLAlchemy: ORM that supports metadata inspection, which can be combined with cx_Oracle for enhanced functionality.


Frontend (Optional for Web UI)


• React.js, Angular, or Vue.js for an interactive web interface.

• Material UI or Bootstrap for enterprise-grade UI components.


Libraries for Profiling


• Pandas: Data profiling and analytics.

• Dataprep or ydata-profiling: For generating column-wise statistics and profiling.


Deployment


• Containerize using Docker.

• Use Kubernetes or AWS ECS for deployment in the cloud.

• CI/CD: GitHub Actions or Jenkins.


2. Features to Build


• Connection Module: Allow users to securely connect to Oracle databases.

• Schema Discovery: Fetch all schemas, tables, and columns.

• Metadata Extraction: Gather column data types, lengths, constraints, and nullability.

• Profiling and Sizing:

• Column distribution.

• Data types and average sizes.

• Null values percentage.

• Export Reports: CSV, Excel, or JSON formats.

• Interactive UI (Optional): Filters, sort options, and visualization.


3. Sample Baseline Code


Database Connection and Metadata Extraction (Python)


import cx_Oracle


def connect_to_oracle(user, password, dsn):

  try:

    connection = cx_Oracle.connect(user, password, dsn)

    print("Connection successful!")

    return connection

  except cx_Oracle.DatabaseError as e:

    print(f"Error: {e}")

    return None


def fetch_table_metadata(connection, schema_name):

  query = f"""

  SELECT table_name, column_name, data_type, data_length, nullable

  FROM all_tab_columns

  WHERE owner = :schema_name

  """

  cursor = connection.cursor()

  cursor.execute(query, {'schema_name': schema_name.upper()})

  results = cursor.fetchall()

  metadata = [

    {

      "table_name": row[0],

      "column_name": row[1],

      "data_type": row[2],

      "data_length": row[3],

      "nullable": row[4]

    }

    for row in results

  ]

  return metadata


# Usage

dsn = cx_Oracle.makedsn("host", 1521, service_name="orcl")

connection = connect_to_oracle("username", "password", dsn)

if connection:

  metadata = fetch_table_metadata(connection, "SCHEMA_NAME")

  for item in metadata:

    print(item)


Profiling Example with Pandas


import pandas as pd


def profile_columns(dataframe):

  profile = {

    "column_name": [],

    "non_null_count": [],

    "unique_count": [],

    "data_type": [],

    "avg_length": [],

  }

  for column in dataframe.columns:

    profile["column_name"].append(column)

    profile["non_null_count"].append(dataframe[column].count())

    profile["unique_count"].append(dataframe[column].nunique())

    profile["data_type"].append(dataframe[column].dtype)

    profile["avg_length"].append(

      dataframe[column].astype(str).str.len().mean()

    )

  return pd.DataFrame(profile)


# Example

data = {"col1": [1, 2, 3], "col2": ["a", "b", None]}

df = pd.DataFrame(data)

print(profile_columns(df))


4. Tools for Further Development


• SQLAlchemy for introspecting database structures:


from sqlalchemy import create_engine, MetaData


engine = create_engine("oracle+cx_oracle://user:password@host:1521/dbname")

metadata = MetaData()

metadata.reflect(bind=engine)

print(metadata.tables)


• FastAPI for creating a REST API around the profiling functionality.


5. Example Applications to Study


• Open-source tools like SQLAlchemy-Utils (metadata utilities).

• Profiling tools like dbt for schema analysis.


Starting with the above code and tools should provide you with a solid foundation for your application. Let me know if you want more specific help!



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