Migrating to duckdb

data_check.py

@@ -1,17 +1,18 @@
+import duckdb
+import os
 import polars as pl
 
-df = pl.read_parquet('data/warehouse/transactions.parquet')
-print("Data loaded from Parquet file:")
-print(df)
 
-relevant_data = df.sql('''
+db = duckdb.connect('/mnt/bulk/data/ynab_data.duckdb')
+
+    # SELECT * FROM gold.transactions
+relevant_data = db.sql('''
     SELECT
         transaction_date,
         sum(transaction_amount) as total
-    FROM self
+    FROM gold.transactions
     GROUP BY transaction_date
     ORDER BY transaction_date DESC
-    '''
+''')
-)
 print("Data after SQL query:")
 print(relevant_data)

main.py

@@ -72,5 +72,3 @@ if __name__ == '__main__':
         else:
             logger.error(f'Program exited with code {exit_code}')
         raise
-
-# test comment

pipeline/duckdb_layer.py

@@ -0,0 +1,241 @@
+"""DuckDB-based silver and gold layer for the YNAB data pipeline."""
+
+import os
+from datetime import date, timedelta
+
+import duckdb
+
+
+class DuckDBLayer:
+    """Orchestrates silver (external base) and gold (views + materialized) layers via DuckDB."""
+
+    def __init__(self, base_path: str, warehouse_path: str, logger):
+        self.base_path = base_path
+        self.warehouse_path = warehouse_path
+        self.logger = logger
+        self.db = None
+        os.makedirs(self.warehouse_path, exist_ok=True)
+        self._init()
+
+    def _silver_parquet_expr(self, entity: str) -> str:
+        return f"read_parquet('{self.base_path}/{entity}.parquet')"
+
+    def _init(self):
+        self.db = duckdb.connect('/mnt/bulk/data/ynab_data.duckdb')
+        self._setup_schemas()
+        self._create_silver_external_tables()
+        self._drop_gold()
+        self._create_gold_views()
+        self._create_gold_dates()
+        self._create_gold_facts()
+
+    def _setup_schemas(self):
+        self.db.execute("CREATE SCHEMA IF NOT EXISTS silver")
+        self.db.execute("CREATE SCHEMA IF NOT EXISTS gold")
+
+    def _create_silver_external_tables(self):
+        entities = ['accounts', 'categories', 'payees', 'transactions', 'scheduled_transactions']
+        for entity in entities:
+            sql = f"CREATE TABLE IF NOT EXISTS silver.{entity} AS SELECT * FROM {self._silver_parquet_expr(entity)}"
+            try:
+                self.db.execute(sql)
+                self.logger.info(f"Created silver.{entity}")
+            except Exception as e:
+                self.logger.error(f"Failed to create silver.{entity}: {e}")
+        self.logger.info("Silver layer initialized")
+
+    def _drop_gold(self):
+        for name in ['accounts', 'categories', 'payees']:
+            self.db.execute(f"DROP VIEW IF EXISTS gold.{name}")
+        self.db.execute("DROP TABLE IF EXISTS gold.dates")
+        self.db.execute("DROP TABLE IF EXISTS gold.transactions")
+        self.db.execute("DROP TABLE IF EXISTS gold.scheduled_transactions")
+
+    # ── gold views (dimensions) ─────
+
+    def _create_gold_accounts_view(self):
+        self.logger.info("Transforming and creating gold.accounts view")
+        sql = """
+            SELECT
+                id AS account_id,
+                name AS account_name,
+                "type" AS account_type,
+                on_budget,
+                closed,
+                COALESCE(CAST(note AS VARCHAR), 'none') AS note,
+                balance / 1000.0 AS balance,
+                cleared_balance / 1000.0 AS cleared_balance,
+                uncleared_balance / 1000.0 AS uncleared_balance,
+                deleted
+            FROM silver.accounts
+        """
+        try:
+            self.db.execute(f"CREATE VIEW gold.accounts AS {sql}")
+            self.logger.info("Created gold.accounts view")
+        except Exception as e:
+            self.logger.error(f"Failed to create gold.accounts view: {e}")
+
+    def _create_gold_categories_view(self):
+        self.logger.info("Transforming and creating gold.categories view")
+        sql = """
+            SELECT
+                id AS category_id,
+                name AS category_name,
+                category_group_name,
+                hidden,
+                COALESCE(CAST(note AS VARCHAR), 'none') AS note,
+                budgeted / 1000.0 AS budgeted,
+                activity / 1000.0 AS activity,
+                balance / 1000.0 AS balance,
+                deleted
+            FROM silver.categories
+        """
+        try:
+            self.db.execute(f"CREATE VIEW gold.categories AS {sql}")
+            self.logger.info("Created gold.categories view")
+        except Exception as e:
+            self.logger.error(f"Failed to create gold.categories view: {e}")
+
+    def _create_gold_payees_view(self):
+        self.logger.info("Transforming and creating gold.payees view")
+        sql = """
+            SELECT
+                id AS payee_id,
+                name AS payee_name,
+                deleted
+            FROM silver.payees
+        """
+        try:
+            self.db.execute(f"CREATE VIEW gold.payees AS {sql}")
+            self.logger.info("Created gold.payees view")
+        except Exception as e:
+            self.logger.error(f"Failed to create gold.payees view: {e}")
+
+    def _create_gold_views(self):
+        self._create_gold_accounts_view()
+        self._create_gold_categories_view()
+        self._create_gold_payees_view()
+
+    # ── gold dates (materialized as Parquet, loaded into DuckDB) ─────
+
+    def _create_gold_dates(self):
+        dates_path = os.path.join(self.warehouse_path, 'dates.parquet')
+        self.logger.info("Creating gold.dates dimension")
+        try:
+            start = date(2020, 1, 1)
+            end = date(2030, 12, 31)
+            days = (end - start).days + 1
+            rows = []
+            for i in range(days):
+                d = start + timedelta(days=i)
+                month_z = str(d.month).zfill(2)
+                day_z = str(d.day).zfill(2)
+                rows.append({
+                    'date_id': f"{d.year}{month_z}{day_z}",
+                    'date': d,
+                    'year': int(d.year),
+                    'month': int(d.month),
+                    'day': int(d.day),
+                    'weekday': int(d.isoweekday()),
+                    'is_weekday': 1 if d.isoweekday() < 6 else 0,
+                })
+
+            import pyarrow as pa
+            import pyarrow.parquet as pq
+            dates_df = pa.Table.from_pylist(rows)
+            dates_df = dates_df.cast(pa.schema([
+                ('date_id', pa.string()),
+                ('date', pa.date32()),
+                ('year', pa.int32()),
+                ('month', pa.int8()),
+                ('day', pa.int8()),
+                ('weekday', pa.int8()),
+                ('is_weekday', pa.int8()),
+            ]))
+            pq.write_table(dates_df, dates_path)
+
+            self.db.execute(f"CREATE TABLE gold.dates AS SELECT * FROM read_parquet('{dates_path}')")
+            self.logger.info(f"Created gold.dates and persisted to {dates_path}")
+        except Exception as e:
+            self.logger.error(f"Failed to create gold.dates: {e}")
+
+    # ── gold facts (materialized as Parquet) ─────
+
+    def _create_gold_transactions_fact(self):
+        transactions_path = os.path.join(self.warehouse_path, 'transactions.parquet')
+        self.logger.info("Transforming and persisting gold.transactions fact")
+        sql = f"""
+            COPY (
+                SELECT
+                    memo,
+                    cleared,
+                    approved,
+                    COALESCE(CAST(flag_color AS VARCHAR), 'none') AS flag_color,
+                    account_id,
+                    payee_id,
+                    category_id,
+                    transfer_account_id,
+                    id AS transaction_id,
+                    CAST(YEAR(CAST(date AS DATE)) AS VARCHAR)
+                        || LPAD(CAST(MONTH(CAST(date AS DATE)) AS VARCHAR), 2, '0')
+                        || LPAD(CAST(DAY(CAST(date AS DATE)) AS VARCHAR), 2, '0') AS transaction_date,
+                    amount / 1000.0 AS transaction_amount,
+                    deleted
+                FROM silver.transactions
+            ) TO '{transactions_path}' (FORMAT PARQUET)
+        """
+        try:
+            self.db.execute(sql)
+            self.logger.info(f"Persisted transactions.fact to {transactions_path}")
+        except Exception as e:
+            self.logger.error(f"Failed to create transactions.fact: {e}")
+
+    def _create_gold_scheduled_transactions_fact(self):
+        st_path = os.path.join(self.warehouse_path, 'scheduled_transactions.parquet')
+        self.logger.info("Transforming and persisting gold.scheduled_transactions fact")
+        sql = f"""
+            COPY (
+                SELECT
+                    CAST(date_first AS DATE) AS date_first,
+                    CAST(date_next AS DATE) AS date_next,
+                    frequency,
+                    COALESCE(memo, 'none') AS memo,
+                    COALESCE(CAST(flag_color AS VARCHAR), 'none') AS flag_color,
+                    account_id,
+                    payee_id,
+                    category_id,
+                    transfer_account_id,
+                    id AS scheduled_transaction_id,
+                    amount / 1000.0 AS scheduled_transaction_amount
+                FROM silver.scheduled_transactions
+            ) TO '{st_path}' (FORMAT PARQUET)
+        """
+        try:
+            self.db.execute(sql)
+            self.logger.info(f"Persisted scheduled_transactions.fact to {st_path}")
+        except Exception as e:
+            self.logger.error(f"Failed to create scheduled_transactions.fact: {e}")
+
+    def _create_gold_facts(self):
+        self._create_gold_transactions_fact()
+        self._create_gold_scheduled_transactions_fact()
+        # Create DuckDB tables from the persistent Parquet files so they're queryable
+        self._register_facts()
+
+    def _register_facts(self):
+        """Register the fact Parquet files as DuckDB tables."""
+        try:
+            self.db.execute(f"CREATE TABLE gold.transactions AS SELECT * FROM read_parquet('{os.path.join(self.warehouse_path, 'transactions.parquet')}')")
+            self.db.execute(f"CREATE TABLE gold.scheduled_transactions AS SELECT * FROM read_parquet('{os.path.join(self.warehouse_path, 'scheduled_transactions.parquet')}')")
+            self.logger.info("Registered fact tables in DuckDB")
+        except Exception as e:
+            self.logger.error(f"Failed to register fact tables: {e}")
+
+    def close(self):
+        if self.db:
+            self.db.close()
+
+
+def get_duckdb_layer(base_path: str, warehouse_path: str, logger) -> DuckDBLayer:
+    """Factory function to create a DuckDB layer and perform all transformations."""
+    return DuckDBLayer(base_path, warehouse_path, logger)

pipeline/pipeline_main.py

@@ -1,6 +1,6 @@
 '''Module to run the data pipeline'''
 
-from pipeline import dimensions, facts, ingest, raw_to_base
+from pipeline import duckdb_layer, ingest, raw_to_base
 
 
 def pipeline_main(config, logger):
@@ -9,11 +9,11 @@ def pipeline_main(config, logger):
 
     ingest.Ingest(config, logger).start_ingestion()
     raw_to_base.RawToBase(config, logger)
-    dimensions.DimAccounts(config,logger)
+
-    dimensions.DimCategories(config,logger)
+    duckdb_layer.get_duckdb_layer(
-    dimensions.DimPayees(config,logger)
+        config['base_data_path'],
-    dimensions.DimDate(config,logger)
+        config['warehouse_data_path'],
-    facts.FactTransactions(config,logger)
+        logger
-    facts.FactScheduledTransactions(config,logger)
+    )
 
     logger.info('Data pipeline completed successfully')

pipeline/raw_to_base.py

@@ -8,7 +8,6 @@ import polars as pl
 
 import config.exit_codes as ec
 
-#test comment for pr check
 
 class RawToBase:
     def __init__(self, config: dict[str, Any],logger):

pyproject.toml

@@ -5,6 +5,7 @@ description = "Add your description here"
 readme = "README.md"
 requires-python = ">=3.13"
 dependencies = [
+    "duckdb>=1.5.5",
     "pandas>=3.0.5",
     "polars>=1.43.0",
     "pyarrow>=25.0.0",

uv.lock

@@ -81,6 +81,7 @@ name = "data-pipeline-for-ynab"
 version = "0.1.0"
 source = { virtual = "." }
 dependencies = [
+    { name = "duckdb" },
     { name = "pandas" },
     { name = "polars" },
     { name = "pyarrow" },
@@ -93,6 +94,7 @@ dependencies = [
 
 [package.metadata]
 requires-dist = [
+    { name = "duckdb", specifier = ">=1.5.5" },
     { name = "pandas", specifier = ">=3.0.5" },
     { name = "polars", specifier = ">=1.43.0" },
     { name = "pyarrow", specifier = ">=25.0.0" },
@@ -103,6 +105,28 @@ requires-dist = [
     { name = "ruff", specifier = ">=0.16.0" },
 ]
 
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 [[package]]
 name = "idna"
 version = "3.18"