Add automatic schema versioning with startup migration

On startup, the app now checks if the database schema version matches
the code. If there's a mismatch or no version exists, it automatically
runs a full data migration before starting.

- Add backend/version.py with SCHEMA_VERSION constant
- Add backend/migration.py with extracted migration logic
- Add SchemaVersion model to track DB version
- Add version check functions to database.py
- Update app.py lifespan to use check_and_migrate_if_needed()
- Simplify migrate_csv_to_db.py to use shared logic

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/app.py

@@ -26,7 +26,7 @@ from .data_loader import (
     geocode_single_postcode,
 )
 from .data_loader import get_data_info as get_db_info
-from .database import init_db
+from .database import check_and_migrate_if_needed
 from .schemas import METRIC_DEFINITIONS, RANKING_COLUMNS, SCHOOL_COLUMNS
 from .utils import clean_for_json
 
@@ -135,16 +135,16 @@ def validate_postcode(postcode: Optional[str]) -> Optional[str]:
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     """Application lifespan - startup and shutdown events."""
-    # Startup: initialize database and pre-load data
+    # Startup: check schema version and migrate if needed
-    print("Starting up: Initializing database...")
+    print("Starting up: Checking database schema...")
-    init_db()  # Ensure tables exist
+    check_and_migrate_if_needed()
 
     print("Loading school data from database...")
     df = load_school_data()
     if df.empty:
-        print("Warning: No data in database. Run the migration script to import data.")
+        print("Warning: No data in database. Check CSV files in data/ folder.")
     else:
-        print("Data loaded successfully.")
+        print(f"Data loaded successfully: {len(df)} records.")
 
     yield  # Application runs here
 

backend/database.py

@@ -2,7 +2,10 @@
 Database connection setup using SQLAlchemy.
 """
 
-from sqlalchemy import create_engine
+from datetime import datetime
+from typing import Optional
+
+from sqlalchemy import create_engine, inspect
 from sqlalchemy.orm import sessionmaker, declarative_base
 from contextlib import contextmanager
 
@@ -65,3 +68,80 @@ def drop_db():
     """
     Base.metadata.drop_all(bind=engine)
 
+
+def get_db_schema_version() -> Optional[int]:
+    """
+    Get the current schema version from the database.
+    Returns None if table doesn't exist or no version is set.
+    """
+    from .models import SchemaVersion  # Import here to avoid circular imports
+
+    # Check if schema_version table exists
+    inspector = inspect(engine)
+    if "schema_version" not in inspector.get_table_names():
+        return None
+
+    try:
+        with get_db_session() as db:
+            row = db.query(SchemaVersion).first()
+            return row.version if row else None
+    except Exception:
+        return None
+
+
+def set_db_schema_version(version: int):
+    """
+    Set/update the schema version in the database.
+    Creates the row if it doesn't exist.
+    """
+    from .models import SchemaVersion
+
+    with get_db_session() as db:
+        row = db.query(SchemaVersion).first()
+        if row:
+            row.version = version
+            row.migrated_at = datetime.utcnow()
+        else:
+            db.add(SchemaVersion(id=1, version=version, migrated_at=datetime.utcnow()))
+
+
+def check_and_migrate_if_needed():
+    """
+    Check schema version and run migration if needed.
+    Called during application startup.
+    """
+    from .version import SCHEMA_VERSION
+    from .migration import run_full_migration
+
+    db_version = get_db_schema_version()
+
+    if db_version == SCHEMA_VERSION:
+        print(f"Schema version {SCHEMA_VERSION} matches. Fast startup.")
+        # Still ensure tables exist (they should if version matches)
+        init_db()
+        return
+
+    if db_version is None:
+        print(f"No schema version found. Running initial migration (v{SCHEMA_VERSION})...")
+    else:
+        print(f"Schema mismatch: DB has v{db_version}, code expects v{SCHEMA_VERSION}")
+        print("Running full migration...")
+
+    try:
+        success = run_full_migration(geocode=False)
+
+        if success:
+            # Ensure schema_version table exists before writing
+            init_db()
+            set_db_schema_version(SCHEMA_VERSION)
+            print(f"Migration complete. Schema version set to {SCHEMA_VERSION}")
+        else:
+            print("Warning: Migration completed but no data was imported.")
+            init_db()
+            set_db_schema_version(SCHEMA_VERSION)
+
+    except Exception as e:
+        print(f"FATAL: Migration failed: {e}")
+        print("Application cannot start. Please check database and CSV files.")
+        raise
+

backend/migration.py

@@ -0,0 +1,413 @@
+"""
+Database migration logic for importing CSV data.
+Used by both CLI script and automatic startup migration.
+"""
+
+import re
+from pathlib import Path
+from typing import Dict, Optional
+
+import numpy as np
+import pandas as pd
+import requests
+
+from .config import settings
+from .database import Base, engine, get_db_session
+from .models import School, SchoolResult
+from .schemas import (
+    COLUMN_MAPPINGS,
+    LA_CODE_TO_NAME,
+    NULL_VALUES,
+    SCHOOL_TYPE_MAP,
+)
+
+
+def parse_numeric(value) -> Optional[float]:
+    """Parse a numeric value, handling special cases."""
+    if pd.isna(value):
+        return None
+    if isinstance(value, (int, float)):
+        return float(value) if not np.isnan(value) else None
+    str_val = str(value).strip().upper()
+    if str_val in NULL_VALUES or str_val == "":
+        return None
+    # Remove percentage signs if present
+    str_val = str_val.replace("%", "")
+    try:
+        return float(str_val)
+    except ValueError:
+        return None
+
+
+def extract_year_from_folder(folder_name: str) -> Optional[int]:
+    """Extract year from folder name like '2023-2024'."""
+    match = re.search(r"(\d{4})-(\d{4})", folder_name)
+    if match:
+        return int(match.group(2))
+    match = re.search(r"(\d{4})", folder_name)
+    if match:
+        return int(match.group(1))
+    return None
+
+
+def geocode_postcodes_bulk(postcodes: list) -> Dict[str, tuple]:
+    """
+    Geocode postcodes in bulk using postcodes.io API.
+    Returns dict of postcode -> (latitude, longitude).
+    """
+    results = {}
+    valid_postcodes = [
+        p.strip().upper()
+        for p in postcodes
+        if p and isinstance(p, str) and len(p.strip()) >= 5
+    ]
+    valid_postcodes = list(set(valid_postcodes))
+
+    if not valid_postcodes:
+        return results
+
+    batch_size = 100
+    total_batches = (len(valid_postcodes) + batch_size - 1) // batch_size
+
+    for i, batch_start in enumerate(range(0, len(valid_postcodes), batch_size)):
+        batch = valid_postcodes[batch_start : batch_start + batch_size]
+        print(
+            f"    Geocoding batch {i + 1}/{total_batches} ({len(batch)} postcodes)..."
+        )
+
+        try:
+            response = requests.post(
+                "https://api.postcodes.io/postcodes",
+                json={"postcodes": batch},
+                timeout=30,
+            )
+            if response.status_code == 200:
+                data = response.json()
+                for item in data.get("result", []):
+                    if item and item.get("result"):
+                        pc = item["query"].upper()
+                        lat = item["result"].get("latitude")
+                        lon = item["result"].get("longitude")
+                        if lat and lon:
+                            results[pc] = (lat, lon)
+        except Exception as e:
+            print(f"    Warning: Geocoding batch failed: {e}")
+
+    return results
+
+
+def load_csv_data(data_dir: Path) -> pd.DataFrame:
+    """Load all CSV data from data directory."""
+    all_data = []
+
+    for folder in sorted(data_dir.iterdir()):
+        if not folder.is_dir():
+            continue
+
+        year = extract_year_from_folder(folder.name)
+        if not year:
+            continue
+
+        # Specifically look for the KS2 results file
+        ks2_file = folder / "england_ks2final.csv"
+        if not ks2_file.exists():
+            continue
+
+        csv_file = ks2_file
+        print(f"  Loading {csv_file.name} (year {year})...")
+
+        try:
+            df = pd.read_csv(csv_file, encoding="latin-1", low_memory=False)
+        except Exception as e:
+            print(f"    Error loading {csv_file}: {e}")
+            continue
+
+        # Rename columns
+        df.rename(columns=COLUMN_MAPPINGS, inplace=True)
+        df["year"] = year
+
+        # Handle local authority name
+        la_name_cols = ["LANAME", "LA (name)", "LA_NAME", "LA NAME"]
+        la_name_col = next((c for c in la_name_cols if c in df.columns), None)
+
+        if la_name_col and la_name_col != "local_authority":
+            df["local_authority"] = df[la_name_col]
+        elif "LEA" in df.columns:
+            df["local_authority_code"] = pd.to_numeric(df["LEA"], errors="coerce")
+            df["local_authority"] = (
+                df["local_authority_code"]
+                .map(LA_CODE_TO_NAME)
+                .fillna(df["LEA"].astype(str))
+            )
+
+        # Store LEA code
+        if "LEA" in df.columns:
+            df["local_authority_code"] = pd.to_numeric(df["LEA"], errors="coerce")
+
+        # Map school type
+        if "school_type_code" in df.columns:
+            df["school_type"] = (
+                df["school_type_code"]
+                .map(SCHOOL_TYPE_MAP)
+                .fillna(df["school_type_code"])
+            )
+
+        # Create combined address
+        addr_parts = ["address1", "address2", "town", "postcode"]
+        for col in addr_parts:
+            if col not in df.columns:
+                df[col] = None
+
+        df["address"] = df.apply(
+            lambda r: ", ".join(
+                str(v)
+                for v in [
+                    r.get("address1"),
+                    r.get("address2"),
+                    r.get("town"),
+                    r.get("postcode"),
+                ]
+                if pd.notna(v) and str(v).strip()
+            ),
+            axis=1,
+        )
+
+        all_data.append(df)
+        print(f"    Loaded {len(df)} records")
+
+    if all_data:
+        result = pd.concat(all_data, ignore_index=True)
+        print(f"\nTotal records loaded: {len(result)}")
+        print(f"Unique schools: {result['urn'].nunique()}")
+        print(f"Years: {sorted(result['year'].unique())}")
+        return result
+
+    return pd.DataFrame()
+
+
+def migrate_data(df: pd.DataFrame, geocode: bool = False):
+    """Migrate DataFrame data to database."""
+
+    # Clean URN column - convert to integer, drop invalid values
+    df = df.copy()
+    df["urn"] = pd.to_numeric(df["urn"], errors="coerce")
+    df = df.dropna(subset=["urn"])
+    df["urn"] = df["urn"].astype(int)
+
+    # Group by URN to get unique schools (use latest year's data)
+    school_data = (
+        df.sort_values("year", ascending=False).groupby("urn").first().reset_index()
+    )
+    print(f"\nMigrating {len(school_data)} unique schools...")
+
+    # Geocode if requested
+    geocoded = {}
+    if geocode and "postcode" in df.columns:
+        print("\nGeocoding postcodes...")
+        postcodes = df["postcode"].dropna().unique().tolist()
+        geocoded = geocode_postcodes_bulk(postcodes)
+        print(f"  Successfully geocoded {len(geocoded)} postcodes")
+
+    with get_db_session() as db:
+        # Create schools
+        urn_to_school_id = {}
+        schools_created = 0
+
+        for _, row in school_data.iterrows():
+            # Safely parse URN - handle None, NaN, whitespace, and invalid values
+            urn_val = row.get("urn")
+            urn = None
+            if pd.notna(urn_val):
+                try:
+                    urn_str = str(urn_val).strip()
+                    if urn_str:
+                        urn = int(float(urn_str))  # Handle "12345.0" format
+                except (ValueError, TypeError):
+                    pass
+            if not urn:
+                continue
+
+            # Skip if we've already added this URN (handles duplicates in source data)
+            if urn in urn_to_school_id:
+                continue
+
+            # Get geocoding data
+            postcode = row.get("postcode")
+            lat, lon = None, None
+            if postcode and pd.notna(postcode):
+                coords = geocoded.get(str(postcode).strip().upper())
+                if coords:
+                    lat, lon = coords
+
+            # Safely parse local_authority_code
+            la_code = None
+            la_code_val = row.get("local_authority_code")
+            if pd.notna(la_code_val):
+                try:
+                    la_code_str = str(la_code_val).strip()
+                    if la_code_str:
+                        la_code = int(float(la_code_str))
+                except (ValueError, TypeError):
+                    pass
+
+            school = School(
+                urn=urn,
+                school_name=row.get("school_name")
+                if pd.notna(row.get("school_name"))
+                else "Unknown",
+                local_authority=row.get("local_authority")
+                if pd.notna(row.get("local_authority"))
+                else None,
+                local_authority_code=la_code,
+                school_type=row.get("school_type")
+                if pd.notna(row.get("school_type"))
+                else None,
+                school_type_code=row.get("school_type_code")
+                if pd.notna(row.get("school_type_code"))
+                else None,
+                religious_denomination=row.get("religious_denomination")
+                if pd.notna(row.get("religious_denomination"))
+                else None,
+                age_range=row.get("age_range")
+                if pd.notna(row.get("age_range"))
+                else None,
+                address1=row.get("address1") if pd.notna(row.get("address1")) else None,
+                address2=row.get("address2") if pd.notna(row.get("address2")) else None,
+                town=row.get("town") if pd.notna(row.get("town")) else None,
+                postcode=row.get("postcode") if pd.notna(row.get("postcode")) else None,
+                latitude=lat,
+                longitude=lon,
+            )
+            db.add(school)
+            db.flush()  # Get the ID
+            urn_to_school_id[urn] = school.id
+            schools_created += 1
+
+            if schools_created % 1000 == 0:
+                print(f"  Created {schools_created} schools...")
+
+        print(f"  Created {schools_created} schools")
+
+        # Create results
+        print(f"\nMigrating {len(df)} yearly results...")
+        results_created = 0
+
+        for _, row in df.iterrows():
+            # Safely parse URN
+            urn_val = row.get("urn")
+            urn = None
+            if pd.notna(urn_val):
+                try:
+                    urn_str = str(urn_val).strip()
+                    if urn_str:
+                        urn = int(float(urn_str))
+                except (ValueError, TypeError):
+                    pass
+            if not urn or urn not in urn_to_school_id:
+                continue
+
+            school_id = urn_to_school_id[urn]
+
+            # Safely parse year
+            year_val = row.get("year")
+            year = None
+            if pd.notna(year_val):
+                try:
+                    year = int(float(str(year_val).strip()))
+                except (ValueError, TypeError):
+                    pass
+            if not year:
+                continue
+
+            result = SchoolResult(
+                school_id=school_id,
+                year=year,
+                total_pupils=parse_numeric(row.get("total_pupils")),
+                eligible_pupils=parse_numeric(row.get("eligible_pupils")),
+                # Expected Standard
+                rwm_expected_pct=parse_numeric(row.get("rwm_expected_pct")),
+                reading_expected_pct=parse_numeric(row.get("reading_expected_pct")),
+                writing_expected_pct=parse_numeric(row.get("writing_expected_pct")),
+                maths_expected_pct=parse_numeric(row.get("maths_expected_pct")),
+                gps_expected_pct=parse_numeric(row.get("gps_expected_pct")),
+                science_expected_pct=parse_numeric(row.get("science_expected_pct")),
+                # Higher Standard
+                rwm_high_pct=parse_numeric(row.get("rwm_high_pct")),
+                reading_high_pct=parse_numeric(row.get("reading_high_pct")),
+                writing_high_pct=parse_numeric(row.get("writing_high_pct")),
+                maths_high_pct=parse_numeric(row.get("maths_high_pct")),
+                gps_high_pct=parse_numeric(row.get("gps_high_pct")),
+                # Progress
+                reading_progress=parse_numeric(row.get("reading_progress")),
+                writing_progress=parse_numeric(row.get("writing_progress")),
+                maths_progress=parse_numeric(row.get("maths_progress")),
+                # Averages
+                reading_avg_score=parse_numeric(row.get("reading_avg_score")),
+                maths_avg_score=parse_numeric(row.get("maths_avg_score")),
+                gps_avg_score=parse_numeric(row.get("gps_avg_score")),
+                # Context
+                disadvantaged_pct=parse_numeric(row.get("disadvantaged_pct")),
+                eal_pct=parse_numeric(row.get("eal_pct")),
+                sen_support_pct=parse_numeric(row.get("sen_support_pct")),
+                sen_ehcp_pct=parse_numeric(row.get("sen_ehcp_pct")),
+                stability_pct=parse_numeric(row.get("stability_pct")),
+                # Absence
+                reading_absence_pct=parse_numeric(row.get("reading_absence_pct")),
+                gps_absence_pct=parse_numeric(row.get("gps_absence_pct")),
+                maths_absence_pct=parse_numeric(row.get("maths_absence_pct")),
+                writing_absence_pct=parse_numeric(row.get("writing_absence_pct")),
+                science_absence_pct=parse_numeric(row.get("science_absence_pct")),
+                # Gender
+                rwm_expected_boys_pct=parse_numeric(row.get("rwm_expected_boys_pct")),
+                rwm_expected_girls_pct=parse_numeric(row.get("rwm_expected_girls_pct")),
+                rwm_high_boys_pct=parse_numeric(row.get("rwm_high_boys_pct")),
+                rwm_high_girls_pct=parse_numeric(row.get("rwm_high_girls_pct")),
+                # Disadvantaged
+                rwm_expected_disadvantaged_pct=parse_numeric(
+                    row.get("rwm_expected_disadvantaged_pct")
+                ),
+                rwm_expected_non_disadvantaged_pct=parse_numeric(
+                    row.get("rwm_expected_non_disadvantaged_pct")
+                ),
+                disadvantaged_gap=parse_numeric(row.get("disadvantaged_gap")),
+                # 3-Year
+                rwm_expected_3yr_pct=parse_numeric(row.get("rwm_expected_3yr_pct")),
+                reading_avg_3yr=parse_numeric(row.get("reading_avg_3yr")),
+                maths_avg_3yr=parse_numeric(row.get("maths_avg_3yr")),
+            )
+            db.add(result)
+            results_created += 1
+
+            if results_created % 10000 == 0:
+                print(f"  Created {results_created} results...")
+                db.flush()
+
+        print(f"  Created {results_created} results")
+
+        # Commit all changes
+        db.commit()
+        print("\nMigration complete!")
+
+
+def run_full_migration(geocode: bool = False) -> bool:
+    """
+    Run a complete migration: drop all tables and reimport from CSV.
+
+    Returns True if successful, False if no data found.
+    Raises exception on error.
+    """
+    print("Dropping existing tables...")
+    Base.metadata.drop_all(bind=engine)
+
+    print("Creating tables...")
+    Base.metadata.create_all(bind=engine)
+
+    print("\nLoading CSV data...")
+    df = load_csv_data(settings.data_dir)
+
+    if df.empty:
+        print("Warning: No CSV data found to migrate!")
+        return False
+
+    migrate_data(df, geocode=geocode)
+    return True

backend/models.py

@@ -3,9 +3,11 @@ SQLAlchemy database models for school data.
 Normalized schema with separate tables for schools and yearly results.
 """
 
+from datetime import datetime
+
 from sqlalchemy import (
     Column, Integer, String, Float, ForeignKey, Index, UniqueConstraint,
-    Text, Boolean
+    Text, Boolean, DateTime
 )
 from sqlalchemy.orm import relationship
 from .database import Base
@@ -133,6 +135,21 @@ class SchoolResult(Base):
         return f"<SchoolResult(school_id={self.school_id}, year={self.year})>"
 
 
+class SchemaVersion(Base):
+    """
+    Tracks database schema version for automatic migrations.
+    Single-row table that stores the current schema version.
+    """
+    __tablename__ = "schema_version"
+
+    id = Column(Integer, primary_key=True, default=1)
+    version = Column(Integer, nullable=False)
+    migrated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
+
+    def __repr__(self):
+        return f"<SchemaVersion(version={self.version}, migrated_at={self.migrated_at})>"
+
+
 # Mapping from CSV columns to model fields
 SCHOOL_FIELD_MAPPING = {
     'urn': 'urn',

backend/version.py

@@ -0,0 +1,22 @@
+"""
+Schema versioning for database migrations.
+
+HOW TO USE:
+- Bump SCHEMA_VERSION when making changes to database models
+- This triggers an automatic full data reimport on next app startup
+
+WHEN TO BUMP:
+- Adding/removing columns in models.py
+- Changing column types or constraints
+- Modifying CSV column mappings in schemas.py
+- Any change that requires fresh data import
+"""
+
+# Current schema version - increment when models change
+SCHEMA_VERSION = 2
+
+# Changelog for documentation
+SCHEMA_CHANGELOG = {
+    1: "Initial schema with School and SchoolResult tables",
+    2: "Added pupil absence fields (reading, maths, gps, writing, science)",
+}

scripts/migrate_csv_to_db.py

@@ -1,16 +1,15 @@
 #!/usr/bin/env python3
 """
-Migration script to import CSV data into PostgreSQL database.
+CLI script for manual database migration.
 
 Usage:
     python scripts/migrate_csv_to_db.py [--drop] [--geocode]
 
 Options:
-    --drop      Drop existing tables before migration
+    --drop      Drop existing tables before migration (full reimport)
     --geocode   Geocode postcodes (requires network access)
 """
 
-import os
 import sys
 from pathlib import Path
 
@@ -18,389 +17,11 @@ from pathlib import Path
 sys.path.insert(0, str(Path(__file__).parent.parent))
 
 import argparse
-import re
-from typing import Dict, Optional
-
-import numpy as np
-import pandas as pd
-import requests
 
 from backend.config import settings
-from backend.database import Base, engine, get_db_session
+from backend.database import Base, engine, init_db, set_db_schema_version
-from backend.models import (
+from backend.migration import load_csv_data, migrate_data, run_full_migration
-    RESULT_FIELD_MAPPING,
+from backend.version import SCHEMA_VERSION
-    SCHOOL_FIELD_MAPPING,
-    School,
-    SchoolResult,
-)
-from backend.schemas import (
-    COLUMN_MAPPINGS,
-    LA_CODE_TO_NAME,
-    NULL_VALUES,
-    NUMERIC_COLUMNS,
-    SCHOOL_TYPE_MAP,
-)
-
-
-def parse_numeric(value) -> Optional[float]:
-    """Parse a numeric value, handling special cases."""
-    if pd.isna(value):
-        return None
-    if isinstance(value, (int, float)):
-        return float(value) if not np.isnan(value) else None
-    str_val = str(value).strip().upper()
-    if str_val in NULL_VALUES or str_val == "":
-        return None
-    # Remove percentage signs if present
-    str_val = str_val.replace("%", "")
-    try:
-        return float(str_val)
-    except ValueError:
-        return None
-
-
-def extract_year_from_folder(folder_name: str) -> Optional[int]:
-    """Extract year from folder name like '2023-2024'."""
-    match = re.search(r"(\d{4})-(\d{4})", folder_name)
-    if match:
-        return int(match.group(2))
-    match = re.search(r"(\d{4})", folder_name)
-    if match:
-        return int(match.group(1))
-    return None
-
-
-def geocode_postcodes_bulk(postcodes: list) -> Dict[str, tuple]:
-    """
-    Geocode postcodes in bulk using postcodes.io API.
-    Returns dict of postcode -> (latitude, longitude).
-    """
-    results = {}
-    valid_postcodes = [
-        p.strip().upper()
-        for p in postcodes
-        if p and isinstance(p, str) and len(p.strip()) >= 5
-    ]
-    valid_postcodes = list(set(valid_postcodes))
-
-    if not valid_postcodes:
-        return results
-
-    batch_size = 100
-    total_batches = (len(valid_postcodes) + batch_size - 1) // batch_size
-
-    for i, batch_start in enumerate(range(0, len(valid_postcodes), batch_size)):
-        batch = valid_postcodes[batch_start : batch_start + batch_size]
-        print(
-            f"    Geocoding batch {i + 1}/{total_batches} ({len(batch)} postcodes)..."
-        )
-
-        try:
-            response = requests.post(
-                "https://api.postcodes.io/postcodes",
-                json={"postcodes": batch},
-                timeout=30,
-            )
-            if response.status_code == 200:
-                data = response.json()
-                for item in data.get("result", []):
-                    if item and item.get("result"):
-                        pc = item["query"].upper()
-                        lat = item["result"].get("latitude")
-                        lon = item["result"].get("longitude")
-                        if lat and lon:
-                            results[pc] = (lat, lon)
-        except Exception as e:
-            print(f"    Warning: Geocoding batch failed: {e}")
-
-    return results
-
-
-def load_csv_data(data_dir: Path) -> pd.DataFrame:
-    """Load all CSV data from data directory."""
-    all_data = []
-
-    for folder in sorted(data_dir.iterdir()):
-        if not folder.is_dir():
-            continue
-
-        year = extract_year_from_folder(folder.name)
-        if not year:
-            continue
-
-        # Specifically look for the KS2 results file
-        ks2_file = folder / "england_ks2final.csv"
-        if not ks2_file.exists():
-            continue
-
-        csv_file = ks2_file
-        print(f"  Loading {csv_file.name} (year {year})...")
-
-        try:
-            df = pd.read_csv(csv_file, encoding="latin-1", low_memory=False)
-        except Exception as e:
-            print(f"    Error loading {csv_file}: {e}")
-            continue
-
-        # Rename columns
-        df.rename(columns=COLUMN_MAPPINGS, inplace=True)
-        df["year"] = year
-
-        # Handle local authority name
-        la_name_cols = ["LANAME", "LA (name)", "LA_NAME", "LA NAME"]
-        la_name_col = next((c for c in la_name_cols if c in df.columns), None)
-
-        if la_name_col and la_name_col != "local_authority":
-            df["local_authority"] = df[la_name_col]
-        elif "LEA" in df.columns:
-            df["local_authority_code"] = pd.to_numeric(df["LEA"], errors="coerce")
-            df["local_authority"] = (
-                df["local_authority_code"]
-                .map(LA_CODE_TO_NAME)
-                .fillna(df["LEA"].astype(str))
-            )
-
-        # Store LEA code
-        if "LEA" in df.columns:
-            df["local_authority_code"] = pd.to_numeric(df["LEA"], errors="coerce")
-
-        # Map school type
-        if "school_type_code" in df.columns:
-            df["school_type"] = (
-                df["school_type_code"]
-                .map(SCHOOL_TYPE_MAP)
-                .fillna(df["school_type_code"])
-            )
-
-        # Create combined address
-        addr_parts = ["address1", "address2", "town", "postcode"]
-        for col in addr_parts:
-            if col not in df.columns:
-                df[col] = None
-
-        df["address"] = df.apply(
-            lambda r: ", ".join(
-                str(v)
-                for v in [
-                    r.get("address1"),
-                    r.get("address2"),
-                    r.get("town"),
-                    r.get("postcode"),
-                ]
-                if pd.notna(v) and str(v).strip()
-            ),
-            axis=1,
-        )
-
-        all_data.append(df)
-        print(f"    Loaded {len(df)} records")
-
-    if all_data:
-        result = pd.concat(all_data, ignore_index=True)
-        print(f"\nTotal records loaded: {len(result)}")
-        print(f"Unique schools: {result['urn'].nunique()}")
-        print(f"Years: {sorted(result['year'].unique())}")
-        return result
-
-    return pd.DataFrame()
-
-
-def migrate_data(df: pd.DataFrame, geocode: bool = False):
-    """Migrate DataFrame data to database."""
-
-    # Clean URN column - convert to integer, drop invalid values
-    df = df.copy()
-    df["urn"] = pd.to_numeric(df["urn"], errors="coerce")
-    df = df.dropna(subset=["urn"])
-    df["urn"] = df["urn"].astype(int)
-
-    # Group by URN to get unique schools (use latest year's data)
-    school_data = (
-        df.sort_values("year", ascending=False).groupby("urn").first().reset_index()
-    )
-    print(f"\nMigrating {len(school_data)} unique schools...")
-
-    # Geocode if requested
-    geocoded = {}
-    if geocode and "postcode" in df.columns:
-        print("\nGeocoding postcodes...")
-        postcodes = df["postcode"].dropna().unique().tolist()
-        geocoded = geocode_postcodes_bulk(postcodes)
-        print(f"  Successfully geocoded {len(geocoded)} postcodes")
-
-    with get_db_session() as db:
-        # Create schools
-        urn_to_school_id = {}
-        schools_created = 0
-
-        for _, row in school_data.iterrows():
-            # Safely parse URN - handle None, NaN, whitespace, and invalid values
-            urn_val = row.get("urn")
-            urn = None
-            if pd.notna(urn_val):
-                try:
-                    urn_str = str(urn_val).strip()
-                    if urn_str:
-                        urn = int(float(urn_str))  # Handle "12345.0" format
-                except (ValueError, TypeError):
-                    pass
-            if not urn:
-                continue
-
-            # Skip if we've already added this URN (handles duplicates in source data)
-            if urn in urn_to_school_id:
-                continue
-
-            # Get geocoding data
-            postcode = row.get("postcode")
-            lat, lon = None, None
-            if postcode and pd.notna(postcode):
-                coords = geocoded.get(str(postcode).strip().upper())
-                if coords:
-                    lat, lon = coords
-
-            # Safely parse local_authority_code
-            la_code = None
-            la_code_val = row.get("local_authority_code")
-            if pd.notna(la_code_val):
-                try:
-                    la_code_str = str(la_code_val).strip()
-                    if la_code_str:
-                        la_code = int(float(la_code_str))
-                except (ValueError, TypeError):
-                    pass
-
-            school = School(
-                urn=urn,
-                school_name=row.get("school_name")
-                if pd.notna(row.get("school_name"))
-                else "Unknown",
-                local_authority=row.get("local_authority")
-                if pd.notna(row.get("local_authority"))
-                else None,
-                local_authority_code=la_code,
-                school_type=row.get("school_type")
-                if pd.notna(row.get("school_type"))
-                else None,
-                school_type_code=row.get("school_type_code")
-                if pd.notna(row.get("school_type_code"))
-                else None,
-                religious_denomination=row.get("religious_denomination")
-                if pd.notna(row.get("religious_denomination"))
-                else None,
-                age_range=row.get("age_range")
-                if pd.notna(row.get("age_range"))
-                else None,
-                address1=row.get("address1") if pd.notna(row.get("address1")) else None,
-                address2=row.get("address2") if pd.notna(row.get("address2")) else None,
-                town=row.get("town") if pd.notna(row.get("town")) else None,
-                postcode=row.get("postcode") if pd.notna(row.get("postcode")) else None,
-                latitude=lat,
-                longitude=lon,
-            )
-            db.add(school)
-            db.flush()  # Get the ID
-            urn_to_school_id[urn] = school.id
-            schools_created += 1
-
-            if schools_created % 1000 == 0:
-                print(f"  Created {schools_created} schools...")
-
-        print(f"  Created {schools_created} schools")
-
-        # Create results
-        print(f"\nMigrating {len(df)} yearly results...")
-        results_created = 0
-
-        for _, row in df.iterrows():
-            # Safely parse URN
-            urn_val = row.get("urn")
-            urn = None
-            if pd.notna(urn_val):
-                try:
-                    urn_str = str(urn_val).strip()
-                    if urn_str:
-                        urn = int(float(urn_str))
-                except (ValueError, TypeError):
-                    pass
-            if not urn or urn not in urn_to_school_id:
-                continue
-
-            school_id = urn_to_school_id[urn]
-
-            # Safely parse year
-            year_val = row.get("year")
-            year = None
-            if pd.notna(year_val):
-                try:
-                    year = int(float(str(year_val).strip()))
-                except (ValueError, TypeError):
-                    pass
-            if not year:
-                continue
-
-            result = SchoolResult(
-                school_id=school_id,
-                year=year,
-                total_pupils=parse_numeric(row.get("total_pupils")),
-                eligible_pupils=parse_numeric(row.get("eligible_pupils")),
-                # Expected Standard
-                rwm_expected_pct=parse_numeric(row.get("rwm_expected_pct")),
-                reading_expected_pct=parse_numeric(row.get("reading_expected_pct")),
-                writing_expected_pct=parse_numeric(row.get("writing_expected_pct")),
-                maths_expected_pct=parse_numeric(row.get("maths_expected_pct")),
-                gps_expected_pct=parse_numeric(row.get("gps_expected_pct")),
-                science_expected_pct=parse_numeric(row.get("science_expected_pct")),
-                # Higher Standard
-                rwm_high_pct=parse_numeric(row.get("rwm_high_pct")),
-                reading_high_pct=parse_numeric(row.get("reading_high_pct")),
-                writing_high_pct=parse_numeric(row.get("writing_high_pct")),
-                maths_high_pct=parse_numeric(row.get("maths_high_pct")),
-                gps_high_pct=parse_numeric(row.get("gps_high_pct")),
-                # Progress
-                reading_progress=parse_numeric(row.get("reading_progress")),
-                writing_progress=parse_numeric(row.get("writing_progress")),
-                maths_progress=parse_numeric(row.get("maths_progress")),
-                # Averages
-                reading_avg_score=parse_numeric(row.get("reading_avg_score")),
-                maths_avg_score=parse_numeric(row.get("maths_avg_score")),
-                gps_avg_score=parse_numeric(row.get("gps_avg_score")),
-                # Context
-                disadvantaged_pct=parse_numeric(row.get("disadvantaged_pct")),
-                eal_pct=parse_numeric(row.get("eal_pct")),
-                sen_support_pct=parse_numeric(row.get("sen_support_pct")),
-                sen_ehcp_pct=parse_numeric(row.get("sen_ehcp_pct")),
-                stability_pct=parse_numeric(row.get("stability_pct")),
-                # Gender
-                rwm_expected_boys_pct=parse_numeric(row.get("rwm_expected_boys_pct")),
-                rwm_expected_girls_pct=parse_numeric(row.get("rwm_expected_girls_pct")),
-                rwm_high_boys_pct=parse_numeric(row.get("rwm_high_boys_pct")),
-                rwm_high_girls_pct=parse_numeric(row.get("rwm_high_girls_pct")),
-                # Disadvantaged
-                rwm_expected_disadvantaged_pct=parse_numeric(
-                    row.get("rwm_expected_disadvantaged_pct")
-                ),
-                rwm_expected_non_disadvantaged_pct=parse_numeric(
-                    row.get("rwm_expected_non_disadvantaged_pct")
-                ),
-                disadvantaged_gap=parse_numeric(row.get("disadvantaged_gap")),
-                # 3-Year
-                rwm_expected_3yr_pct=parse_numeric(row.get("rwm_expected_3yr_pct")),
-                reading_avg_3yr=parse_numeric(row.get("reading_avg_3yr")),
-                maths_avg_3yr=parse_numeric(row.get("maths_avg_3yr")),
-            )
-            db.add(result)
-            results_created += 1
-
-            if results_created % 10000 == 0:
-                print(f"  Created {results_created} results...")
-                db.flush()
-
-        print(f"  Created {results_created} results")
-
-        # Commit all changes
-        db.commit()
-        print("\nMigration complete!")
 
 
 def main():
@@ -418,24 +39,29 @@ def main():
     print("=" * 60)
     print(f"\nDatabase: {settings.database_url.split('@')[-1]}")
     print(f"Data directory: {settings.data_dir}")
+    print(f"Target schema version: {SCHEMA_VERSION}")
 
     if args.drop:
-        print("\n⚠️  Dropping existing tables...")
+        print("\nRunning full migration (drop + reimport)...")
-        Base.metadata.drop_all(bind=engine)
+        success = run_full_migration(geocode=args.geocode)
+    else:
+        print("\nCreating tables (preserving existing data)...")
+        init_db()
+        print("\nLoading CSV data...")
+        df = load_csv_data(settings.data_dir)
+        if df.empty:
+            print("No data found to migrate!")
+            return 1
+        migrate_data(df, geocode=args.geocode)
+        success = True
 
-    print("\nCreating tables...")
+    if success:
-    Base.metadata.create_all(bind=engine)
+        # Ensure schema_version table exists
+        init_db()
+        set_db_schema_version(SCHEMA_VERSION)
+        print(f"\nSchema version set to {SCHEMA_VERSION}")
 
-    print("\nLoading CSV data...")
+    return 0 if success else 1
-    df = load_csv_data(settings.data_dir)
-
-    if df.empty:
-        print("No data found to migrate!")
-        return 1
-
-    migrate_data(df, geocode=args.geocode)
-
-    return 0
 
 
 if __name__ == "__main__":