Data Architecture

Purpose

Guide architects and platform engineers through strategic data architecture decisions for modern cloud-native data platforms.

When to Use This Skill

Invoke this skill when:

• Designing a new data platform or modernizing legacy systems
• Choosing between data lake, data warehouse, or data lakehouse
• Deciding on data modeling approaches (dimensional, normalized, data vault, wide tables)
• Evaluating centralized vs data mesh architecture
• Selecting open table formats (Apache Iceberg, Delta Lake, Apache Hudi)
• Designing medallion architecture (bronze, silver, gold layers)
• Implementing data governance and cataloging

Core Concepts

1. Storage Paradigms

Three primary patterns for analytical data storage:

Data Lake: Centralized repository for raw data at scale

• Schema-on-read, cost-optimized ($0.02-0.03/GB/month)
• Use when: Diverse data sources, exploratory analytics, ML/AI training data

Data Warehouse: Structured repository optimized for BI

• Schema-on-write, ACID transactions, fast queries
• Use when: Known BI requirements, strong governance needed

Data Lakehouse: Hybrid combining lake flexibility with warehouse reliability

• Open table formats (Iceberg, Delta Lake), ACID on object storage
• Use when: Mixed BI + ML workloads, cost optimization (60-80% cheaper than warehouse)

Decision Framework:

• BI/Reporting only + Known queries → Data Warehouse
• ML/AI primary + Raw data needed → Data Lake or Lakehouse
• Mixed BI + ML + Cost optimization → Data Lakehouse (recommended)
• Exploratory/Unknown use cases → Data Lake

For detailed comparison, see references/storage-paradigms.md.

2. Data Modeling Approaches

Four primary modeling patterns:

Dimensional (Kimball): Star/snowflake schemas for BI

• Use when: Known query patterns, BI dashboards, trend analysis

Normalized (3NF): Eliminate redundancy for transactional systems

• Use when: OLTP systems, frequent updates, strong consistency

Data Vault 2.0: Flexible model with complete audit trail

• Use when: Compliance requirements, multiple sources, agile warehousing

Wide Tables: Denormalized, optimized for columnar storage

• Use when: ML feature stores, data science notebooks, high-performance dashboards

Decision Framework:

• Analytical (BI) + Known queries → Dimensional (Star Schema)
• Transactional (OLTP) → Normalized (3NF)
• Compliance/Audit → Data Vault 2.0
• Data Science/ML → Wide Tables

For detailed patterns, see references/modeling-approaches.md.

3. Data Mesh Principles

Decentralized architecture for large organizations (>500 people).

Four Core Principles:

1. Domain-oriented decentralization
2. Data as a product (SLAs, quality, documentation)
3. Self-serve data infrastructure
4. Federated computational governance

Readiness Assessment (Score 1-5 each):

1. Domain clarity
2. Team maturity
3. Platform capability
4. Governance maturity
5. Scale need
6. Organizational buy-in

Scoring: 24-30: Strong candidate | 18-23: Hybrid | 12-17: Build foundation first | 6-11: Centralized

Red Flags: Small org (<100 people), unclear domains, no platform team, weak governance

For full guide, see references/data-mesh-guide.md.

4. Medallion Architecture

Standard lakehouse pattern: Bronze (raw) → Silver (cleaned) → Gold (business-level)

Bronze Layer: Exact copy of source data, immutable, append-only

Silver Layer: Validated, deduplicated, typed data

Gold Layer: Business logic, aggregates, dimensional models, ML features

Data Quality by Layer:

• Bronze → Silver: Schema validation, type checks, deduplication
• Silver → Gold: Business rule validation, referential integrity
• Gold: Anomaly detection, statistical checks

For patterns, see references/medallion-pattern.md.

5. Open Table Formats

Enable ACID transactions on data lakes:

Apache Iceberg: Multi-engine, vendor-neutral (Context7: 79.7 score)

• Use when: Avoid vendor lock-in, multi-engine flexibility

Delta Lake: Databricks ecosystem, Spark-optimized

• Use when: Committed to Databricks

Apache Hudi: Optimized for CDC and frequent upserts

• Use when: CDC-heavy workloads

Recommendation: Apache Iceberg for new projects (vendor-neutral, broadest support)

For comparison, see references/table-formats.md.

6. Modern Data Stack

Standard Layers:

• Ingestion: Fivetran, Airbyte, Kafka
• Storage: Snowflake, Databricks, BigQuery
• Transformation: dbt (Context7: 87.0 score), Spark
• Orchestration: Airflow, Dagster, Prefect
• Visualization: Tableau, Looker, Power BI
• Governance: DataHub, Alation, Great Expectations

Tool Selection:

• Fivetran vs Airbyte: Pre-built connectors vs cost-sensitive
• Snowflake vs Databricks: BI-focused vs ML-focused
• dbt vs Spark: SQL-based vs large-scale processing

For detailed recommendations, see references/tool-recommendations.md and references/modern-data-stack.md.

7. Data Governance

Data Catalog: Searchable inventory (DataHub, Alation, Collibra)

Data Lineage: Track data flow (OpenLineage, Marquez)

Data Quality: Validation and testing (Great Expectations, Soda, dbt tests)

Access Control:

• RBAC: Role-based (sales_analyst role)
• ABAC: Attribute-based (row-level security)
• Column-level: Dynamic data masking for PII

For governance patterns, see references/governance-patterns.md.

Decision Frameworks

Framework 1: Storage Paradigm Selection

Step 1: Identify Primary Use Case

• BI/Reporting only → Data Warehouse
• ML/AI primary → Data Lake or Lakehouse
• Mixed BI + ML → Data Lakehouse
• Exploratory → Data Lake

Step 2: Evaluate Budget

• High budget, known queries → Data Warehouse
• Cost-sensitive, flexible → Data Lakehouse

Recommendation by Org Size:

• Startup (<50): Data Warehouse (simplicity)
• Growth (50-500): Data Lakehouse (balance)
• Enterprise (>500): Hybrid or unified Lakehouse

See references/decision-frameworks.md.

Framework 2: Data Modeling Approach

Decision Tree:

• Analytical (BI) workload → Dimensional or Wide Tables
• Transactional (OLTP) → Normalized (3NF)
• Compliance/Audit → Data Vault 2.0
• Data Science/ML → Wide Tables

See references/decision-frameworks.md.

Framework 3: Data Mesh Readiness

Use 6-factor assessment. Score interpretation:

• 24-30: Proceed with data mesh
• 18-23: Hybrid approach
• 12-17: Build foundation first
• 6-11: Centralized

See references/decision-frameworks.md.

Framework 4: Open Table Format Selection

Decision Tree:

• Multi-engine flexibility → Apache Iceberg
• Databricks ecosystem → Delta Lake
• Frequent upserts/CDC → Apache Hudi

Recommendation: Apache Iceberg for new projects

See references/decision-frameworks.md.

Common Scenarios

Startup Data Platform

Context: 50-person startup, PostgreSQL + MongoDB + Stripe

Recommendation:

• Storage: BigQuery or Snowflake
• Ingestion: Airbyte or Fivetran
• Transformation: dbt
• Orchestration: dbt Cloud
• Architecture: Simple data warehouse

See references/scenarios.md.

Enterprise Modernization

Context: Legacy Oracle warehouse, need cloud migration

Recommendation:

• Storage: Data Lakehouse (Databricks or Snowflake with Iceberg)
• Strategy: Incremental migration with CDC
• Architecture: Medallion (bronze, silver, gold)
• Cost Savings: 60-80%

See references/scenarios.md.

Data Mesh Assessment

Context: 200-person company, 5-person central data team

Recommendation: NOT YET. Build foundation first.

• Organization too small (<500 recommended)
• Central team not yet bottleneck
• Invest in self-serve platform and governance

See references/scenarios.md.

Tool Recommendations

Research-Validated (Context7, December 2025)

dbt: Score 87.0, 3,532+ code snippets

• SQL-based transformations, version control, testing
• Industry standard for data transformation

Apache Iceberg: Score 79.7, 832+ code snippets

• Open table format, multi-engine, vendor-neutral
• Production-ready (Netflix, Apple, Adobe)

Tool Stack by Use Case:

Startup: BigQuery + Airbyte + dbt + Metabase (<$1K/month)

Growth: Snowflake + Fivetran + dbt + Airflow + Tableau ($10K-50K/month)

Enterprise: Snowflake + Databricks + Fivetran + Kafka + dbt + Airflow + Alation ($50K-500K/month)

See references/tool-recommendations.md.

Implementation Patterns

Pattern 1: Medallion Architecture

sql
-- Bronze: Raw ingestion
CREATE TABLE bronze.raw_customers (_ingested_at TIMESTAMP, _raw_data STRING);

-- Silver: Cleaned
CREATE TABLE silver.customers AS
SELECT json_extract(_raw_data, '$.id') AS customer_id, ...
FROM bronze.raw_customers
QUALIFY ROW_NUMBER() OVER (PARTITION BY customer_id ORDER BY _ingested_at DESC) = 1;

-- Gold: Business-level
CREATE TABLE gold.fact_sales AS
SELECT s.order_id, d.date_key, c.customer_key, ...
FROM silver.sales s
JOIN gold.dim_date d ON s.order_date = d.date;

Pattern 2: Apache Iceberg Table

sql
CREATE TABLE catalog.db.sales (order_id BIGINT, amount DECIMAL(10,2))
USING iceberg
PARTITIONED BY (days(order_date));

-- Time travel
SELECT * FROM catalog.db.sales TIMESTAMP AS OF '2025-01-01';

Pattern 3: dbt Transformation

sql
-- models/staging/stg_customers.sql
WITH source AS (SELECT * FROM {{ source('raw', 'customers') }}),
cleaned AS (
  SELECT customer_id, UPPER(customer_name) AS customer_name
  FROM source WHERE customer_id IS NOT NULL
)
SELECT * FROM cleaned

For complete examples, see examples/.

Best Practices

1. Start simple: Avoid over-engineering; begin with warehouse or basic lakehouse
2. Invest in governance early: Catalog, lineage, quality from day one
3. Medallion architecture: Use bronze-silver-gold for clear quality layers
4. Open table formats: Prefer Iceberg or Delta Lake to avoid vendor lock-in
5. Assess mesh readiness: Don't decentralize prematurely (<500 people)
6. Automate quality: Integrate tests (Great Expectations, dbt) into CI/CD
7. Monitor pipelines: Observability is critical (freshness, quality, health)
8. Document as code: Use dbt docs, DataHub, YAML for self-service
9. Incremental loading: Only load new/changed data (watermark columns)
10. Business alignment: Align architecture to outcomes, not just technologies

Anti-Patterns

• ❌ Data swamp: Lake without governance or cataloging
• ❌ Premature mesh: Mesh before organizational readiness
• ❌ Tool sprawl: Too many tools without integration
• ❌ No quality checks: "Garbage in, garbage out"
• ❌ Centralized bottleneck: Single team in large org (>500 people)
• ❌ Vendor lock-in: Proprietary formats without migration path
• ❌ No lineage: Can't answer "where did this come from?"
• ❌ Over-engineering: Complex architecture for simple use cases

Integration with Other Skills

Direct Dependencies:

• ingesting-data: ETL/ELT mechanics, Fivetran, Airbyte implementation
• data-transformation: dbt and Dataform detailed implementation
• streaming-data: Kafka, Flink for real-time pipelines

Complementary:

• databases-relational: PostgreSQL, MySQL as source systems
• databases-document: MongoDB, DynamoDB as sources
• ai-data-engineering: Feature stores, ML training pipelines
• designing-distributed-systems: CAP theorem, consistency models
• observability: Monitoring pipeline health, data quality metrics

Downstream:

• visualizing-data: BI and dashboard patterns
• sql-optimization: Query performance tuning

Common Workflows:

End-to-End Analytics:

data-architecture (warehouse) → ingesting-data (Fivetran) →
data-transformation (dbt) → visualizing-data (Tableau)

Data Platform for AI/ML:

data-architecture (lakehouse) → ingesting-data (Kafka) →
data-transformation (dbt features) → ai-data-engineering (feature store)

Further Reading

Reference Files:

• decision-frameworks.md - All 4 decision frameworks in detail
• storage-paradigms.md - Lake vs warehouse vs lakehouse
• modeling-approaches.md - Dimensional, normalized, data vault, wide
• data-mesh-guide.md - Data mesh principles and implementation
• medallion-pattern.md - Bronze, silver, gold layers
• table-formats.md - Iceberg, Delta Lake, Hudi comparison
• tool-recommendations.md - Tool analysis and recommendations
• modern-data-stack.md - Tool categories and selection
• governance-patterns.md - Catalog, lineage, quality, access control
• scenarios.md - Startup, enterprise, data mesh scenarios

Examples:

• examples/dbt-project/ - dbt project with medallion architecture

External Resources:

• Apache Iceberg: https://iceberg.apache.org/
• dbt Documentation: https://docs.getdbt.com/
• Data Mesh (Zhamak Dehghani): https://www.datamesh-architecture.com/
• Databricks Medallion: https://www.databricks.com/glossary/medallion-architecture