diff --git a/spinedb_api/db_mapping_add_mixin.py b/spinedb_api/db_mapping_add_mixin.py
index abd3b8db..a8447d14 100644
--- a/spinedb_api/db_mapping_add_mixin.py
+++ b/spinedb_api/db_mapping_add_mixin.py
@@ -17,7 +17,7 @@
 from datetime import datetime
 from sqlalchemy import func, Table, Column, Integer, String, null, select
 from sqlalchemy.exc import DBAPIError
-from .exception import SpineDBAPIError
+from .exception import SpineDBAPIError, SpineIntegrityError
 from .helpers import get_relationship_entity_class_items, get_relationship_entity_items
 
 
@@ -149,15 +149,23 @@ def add_items(
             list(SpineIntegrityError): found violations
         """
         if readd:
-            self._readd_items(tablename, *items)
-            return items if return_items else {x["id"] for x in items}, []
+            try:
+                self._readd_items(tablename, *items)
+                return items if return_items else {x["id"] for x in items}, []
+            except SpineDBAPIError as e:
+                return set(), [e]
+
         if check:
             checked_items, intgr_error_log = self.check_items(
                 tablename, *items, for_update=False, strict=strict, cache=cache
             )
         else:
             checked_items, intgr_error_log = list(items), []
-        ids = self._add_items(tablename, *checked_items)
+        try:
+            ids = self._add_items(tablename, *checked_items)
+        except DBAPIError as e:
+            intgr_error_log.append(SpineIntegrityError(f"Fail to add items: {e.orig.args}"))
+            return set(), intgr_error_log
         if return_items:
             return checked_items, intgr_error_log
         if return_dups:
diff --git a/spinedb_api/db_mapping_commit_mixin.py b/spinedb_api/db_mapping_commit_mixin.py
index 025e186d..4bf39256 100644
--- a/spinedb_api/db_mapping_commit_mixin.py
+++ b/spinedb_api/db_mapping_commit_mixin.py
@@ -15,6 +15,7 @@
 """
 
 from datetime import datetime, timezone
+import sqlalchemy.exc
 from .exception import SpineDBAPIError
 
 
@@ -42,7 +43,10 @@ def _get_sqlite_lock(self):
     def _make_commit_id(self):
         if self._commit_id is None:
             if self.committing:
-                self._get_sqlite_lock()
+                try:
+                    self._get_sqlite_lock()
+                except:
+                    raise SpineDBAPIError("Committing failed due to the database being locked")
                 self._commit_id = self._do_make_commit_id(self.connection)
             else:
                 with self.engine.begin() as connection:
@@ -66,7 +70,10 @@ def commit_session(self, comment):
         user = self.username
         date = datetime.now(timezone.utc)
         upd = commit.update().where(commit.c.id == self._make_commit_id())
-        self._checked_execute(upd, dict(user=user, date=date, comment=comment))
+        try:
+            self._checked_execute(upd, dict(user=user, date=date, comment=comment))
+        except sqlalchemy.exc.DBAPIError as e:
+            raise SpineDBAPIError(f"Fail to commit: {e}")
         self.session.commit()
         self._commit_id = None
         if self._memory:
diff --git a/spinedb_api/db_mapping_remove_mixin.py b/spinedb_api/db_mapping_remove_mixin.py
index f4718a3f..7ca479f0 100644
--- a/spinedb_api/db_mapping_remove_mixin.py
+++ b/spinedb_api/db_mapping_remove_mixin.py
@@ -77,13 +77,16 @@ def cascading_ids(self, cache=None, **kwargs):
             cascading_ids (dict): cascading ids keyed by table name
         """
         if cache is None:
-            cache = self.make_cache(
-                set(kwargs),
-                include_descendants=True,
-                force_tablenames={"entity_metadata", "parameter_value_metadata"}
-                if any(x in kwargs for x in ("entity_metadata", "parameter_value_metadata", "metadata"))
-                else None,
-            )
+            try:
+                cache = self.make_cache(
+                    set(kwargs),
+                    include_descendants=True,
+                    force_tablenames={"entity_metadata", "parameter_value_metadata"}
+                    if any(x in kwargs for x in ("entity_metadata", "parameter_value_metadata", "metadata"))
+                    else None,
+                )
+            except DBAPIError as e:
+                raise SpineDBAPIError(f"Fail to get cascading ids: {e.orig.args}")
         ids = {}
         self._merge(ids, self._object_class_cascading_ids(kwargs.get("object_class", set()), cache))
         self._merge(ids, self._object_cascading_ids(kwargs.get("object", set()), cache))
diff --git a/spinedb_api/db_mapping_update_mixin.py b/spinedb_api/db_mapping_update_mixin.py
index e2c4fd62..e36fb2f7 100644
--- a/spinedb_api/db_mapping_update_mixin.py
+++ b/spinedb_api/db_mapping_update_mixin.py
@@ -15,7 +15,7 @@
 from collections import Counter
 from sqlalchemy.exc import DBAPIError
 from sqlalchemy.sql.expression import bindparam
-from .exception import SpineDBAPIError
+from .exception import SpineDBAPIError, SpineIntegrityError
 
 
 class DatabaseMappingUpdateMixin:
@@ -78,7 +78,10 @@ def update_items(self, tablename, *items, check=True, strict=False, return_items
             )
         else:
             checked_items, intgr_error_log = list(items), []
-        updated_ids = self._update_items(tablename, *checked_items)
+        try:
+            updated_ids = self._update_items(tablename, *checked_items)
+        except SpineDBAPIError as e:
+            intgr_error_log.append(f"Fail to update items: {e}")
         if return_items:
             return checked_items, intgr_error_log
         return updated_ids, intgr_error_log