Migrate from duckdb to sqlite

terms-database/Dockerfile

@@ -2,7 +2,7 @@ FROM python:3.14-slim
 
 WORKDIR /app
 
-RUN pip install --no-cache-dir flask duckdb gunicorn
+RUN pip install --no-cache-dir flask gunicorn
 
 COPY . .
 

terms-database/search.py

@@ -1,29 +1,31 @@
 #!/usr/bin/env -S uv run --script
 # /// script
-# dependencies = ["duckdb"]
+# dependencies = []
 # ///
-"""Full-text search over MPI term database. Queries unified_terms_flat via DuckDB LIKE.
+"""Full-text search over MPI term database (SQLite).
 
 Module usage:
-    from search import search_terms
-    results = search_terms("空性")
-    results = search_terms("空性", limit=5, loc="心经", src="佛教术语")
+    from search import search
+    results = search("空性")
+    results = search("空性", limit=5, loc="心经", src="佛教术语")
     # returns list of dicts: {zh, en, loc, source}
 
 CLI usage:
-    python search.py <query> [limit]
-    python search.py 空性 loc:心经 src:公案
+    toolkit/terms-database/search.py <query> [limit]
+    toolkit/terms-database/search.py 空性 loc:心经 src:公案
 """
 
 import sys
 import os
-import duckdb
+import sqlite3
 
-DB = os.path.join(os.path.dirname(os.path.abspath(__file__)), "termlib.duckdb")
+DB = os.path.join(os.path.dirname(os.path.abspath(__file__)), "termlib.sqlite")
 
 
 def _connect():
-    return duckdb.connect(DB, read_only=True)
+    con = sqlite3.connect(DB)
+    con.execute("PRAGMA journal_mode=WAL")
+    return con
 
 
 def _search_rows(con, query, loc=None, src=None, limit=None):
@@ -45,7 +47,7 @@ def _search_rows(con, query, loc=None, src=None, limit=None):
         where += " AND source = ?"
         params.append(src)
 
-    sql = f"SELECT zh, en, loc, source FROM unified_terms_flat WHERE {where}"
+    sql = f"SELECT zh, en, loc, source FROM terms WHERE {where}"
     if limit is not None:
         sql += " LIMIT ?"
         params.append(limit)
@@ -55,7 +57,7 @@ def _search_rows(con, query, loc=None, src=None, limit=None):
 
 def search(query, loc=None, src=None, limit=20):
     """Search the terms database. Returns list of {zh, en, loc, source} dicts.
-    
+
     query: str — space-separated search terms (AND logic)
     loc: str — filter by loc column (LIKE match)
     src: str — filter by source column (exact match)

terms-database/server.py

@@ -2,21 +2,27 @@
 import sys, os
 sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
 
-import duckdb
+import sqlite3
 from flask import Flask, request, jsonify, render_template
 import search as s
 
 app = Flask(__name__)
 
+def _connect():
+    con = sqlite3.connect(s.DB)
+    con.execute("PRAGMA journal_mode=WAL")
+    return con
+
+
 def do_search(q, loc, src, limit):
-    with duckdb.connect(s.DB, read_only=True) as con:
-        rows = s.search(con, q, loc, src, limit)
-    return [{'zh': r[0], 'en': r[1], 'loc': r[2] or None, 'source': r[3]} for r in rows]
+    rows = s.search(q, loc=loc, src=src, limit=limit)
+    return [{'zh': r['zh'], 'en': r['en'], 'loc': r['loc'] or None, 'source': r['source']} for r in rows]
+
 
 def do_sources():
-    with duckdb.connect(s.DB, read_only=True) as con:
+    with _connect() as con:
         rows = con.execute(
-            'SELECT source, COUNT(*) AS cnt FROM unified_terms_flat GROUP BY source ORDER BY cnt DESC'
+            'SELECT source, COUNT(*) AS cnt FROM terms GROUP BY source ORDER BY cnt DESC'
         ).fetchall()
     return [{'source': r[0], 'count': r[1]} for r in rows]