db (schema): create virtual table for FTS + migration

rel 361

sat/memory/sqla_mapping.py

@@ -23,7 +23,7 @@ import time
 import enum
 from sqlalchemy import (
     MetaData, Column, Integer, Text, Float, Boolean, DateTime, Enum, JSON, ForeignKey,
-    UniqueConstraint, Index
+    UniqueConstraint, Index, DDL, event
 )
 
 from sqlalchemy.orm import declarative_base, relationship
@@ -56,7 +56,7 @@ class SyncState(enum.Enum):
     COMPLETED = 2
     #: something wrong happened during synchronisation, won't sync
     ERROR = 3
-    #: synchronisation won't be done even if a syncing analyser match
+    #: synchronisation won't be done even if a syncing analyser matches
     NO_SYNC = 4
 
 
@@ -529,3 +529,48 @@ class PubsubItem(Base):
     parsed = Column(JSON)
 
     node = relationship("PubsubNode", back_populates="items")
+
+
+## Full-Text Search
+
+# create
+
+@event.listens_for(PubsubItem.__table__, "after_create")
+def fts_create(target, connection, **kw):
+    """Full-Text Search table creation"""
+    if connection.engine.name == "sqlite":
+        # Using SQLite FTS5
+        queries = [
+            "CREATE VIRTUAL TABLE pubsub_items_fts "
+            "USING fts5(data, content=pubsub_items, content_rowid=id)",
+            "CREATE TRIGGER pubsub_items_fts_sync_ins AFTER INSERT ON pubsub_items BEGIN"
+            "  INSERT INTO pubsub_items_fts(rowid, data) VALUES (new.id, new.data);"
+            "END",
+            "CREATE TRIGGER pubsub_items_fts_sync_del AFTER DELETE ON pubsub_items BEGIN"
+            "  INSERT INTO pubsub_items_fts(pubsub_items_fts, rowid, data) "
+            "VALUES('delete', old.id, old.data);"
+            "END",
+            "CREATE TRIGGER pubsub_items_fts_sync_upd AFTER UPDATE ON pubsub_items BEGIN"
+            "  INSERT INTO pubsub_items_fts(pubsub_items_fts, rowid, data) VALUES"
+            "('delete', old.id, old.data);"
+            "  INSERT INTO pubsub_items_fts(rowid, data) VALUES(new.id, new.data);"
+            "END"
+        ]
+        for q in queries:
+            connection.execute(DDL(q))
+
+# drop
+
+@event.listens_for(PubsubItem.__table__, "before_drop")
+def fts_drop(target, connection, **kw):
+    "Full-Text Search table drop" ""
+    if connection.engine.name == "sqlite":
+        # Using SQLite FTS5
+        queries = [
+            "DROP TRIGGER IF EXISTS pubsub_items_fts_sync_ins",
+            "DROP TRIGGER IF EXISTS pubsub_items_fts_sync_del",
+            "DROP TRIGGER IF EXISTS pubsub_items_fts_sync_upd",
+            "DROP TABLE IF EXISTS pubsub_items_fts",
+        ]
+        for q in queries:
+            connection.execute(DDL(q))