diff --git a/lib/taskana-core/src/main/resources/sql/db2/taskana_schema_update_2.0.2_to_3.0.0_db2.sql b/lib/taskana-core/src/main/resources/sql/db2/taskana_schema_update_2.0.2_to_3.0.0_db2.sql
index 33bdc077a..f05f74365 100644
--- a/lib/taskana-core/src/main/resources/sql/db2/taskana_schema_update_2.0.2_to_3.0.0_db2.sql
+++ b/lib/taskana-core/src/main/resources/sql/db2/taskana_schema_update_2.0.2_to_3.0.0_db2.sql
@@ -62,5 +62,5 @@ ALTER TABLE OBJECT_REFERENCE ALTER COLUMN SYSTEM_INSTANCE DROP NOT NULL;
 REORG TABLE OBJECT_REFERENCE;
 
 ALTER TABLE TASK ALTER COLUMN POR_SYSTEM DROP NOT NULL;
-ALTER TABLE TASK ALTER COLUMN POR_SYSTEM_INSTANCE DROP NOT NULL;
+ALTER TABLE TASK ALTER COLUMN POR_INSTANCE DROP NOT NULL;
 REORG TABLE TASK;
\ No newline at end of file
diff --git a/lib/taskana-core/src/main/resources/sql/h2/taskana_schema_update_2.0.2_to_3.0.0_h2.sql b/lib/taskana-core/src/main/resources/sql/h2/taskana_schema_update_2.0.2_to_3.0.0_h2.sql
index 024fc1aae..fb2c94866 100644
--- a/lib/taskana-core/src/main/resources/sql/h2/taskana_schema_update_2.0.2_to_3.0.0_h2.sql
+++ b/lib/taskana-core/src/main/resources/sql/h2/taskana_schema_update_2.0.2_to_3.0.0_h2.sql
@@ -42,9 +42,9 @@ CREATE TABLE CONFIGURATION (
 
 -- TSK-1227 allow null values in OBJECT_REFERENCE#SYSTEM and OBJECT_REFERENCE#SYSTEM_INSTANCE
 
-ALTER TABLE OBJECT_REFERENCE ALTER COLUMN SYSTEM DROP NOT NULL;
-ALTER TABLE OBJECT_REFERENCE ALTER COLUMN SYSTEM_INSTANCE DROP NOT NULL;
+ALTER TABLE OBJECT_REFERENCE ALTER COLUMN SYSTEM SET NULL;
+ALTER TABLE OBJECT_REFERENCE ALTER COLUMN SYSTEM_INSTANCE SET NULL;
 
-ALTER TABLE TASK ALTER COLUMN POR_SYSTEM DROP NOT NULL;
-ALTER TABLE TASK ALTER COLUMN POR_SYSTEM_INSTANCE DROP NOT NULL;
+ALTER TABLE TASK ALTER COLUMN POR_SYSTEM SET NULL;
+ALTER TABLE TASK ALTER COLUMN POR_INSTANCE SET NULL;
 
diff --git a/lib/taskana-core/src/main/resources/sql/postgres/taskana_schema_update_2.0.2_to_3.0.0_postgres.sql b/lib/taskana-core/src/main/resources/sql/postgres/taskana_schema_update_2.0.2_to_3.0.0_postgres.sql
index b82501f42..ca35524e5 100644
--- a/lib/taskana-core/src/main/resources/sql/postgres/taskana_schema_update_2.0.2_to_3.0.0_postgres.sql
+++ b/lib/taskana-core/src/main/resources/sql/postgres/taskana_schema_update_2.0.2_to_3.0.0_postgres.sql
@@ -42,9 +42,10 @@ CREATE TABLE CONFIGURATION (
 
 -- TSK-1227 allow null values in OBJECT_REFERENCE#SYSTEM and OBJECT_REFERENCE#SYSTEM_INSTANCE
 
-ALTER TABLE OBJECT_REFERENCE ALTER COLUMN SYSTEM SET NULL;
-ALTER TABLE OBJECT_REFERENCE ALTER COLUMN SYSTEM_INSTANCE SET NULL;
+ALTER TABLE OBJECT_REFERENCE ALTER COLUMN SYSTEM DROP NOT NULL;
+ALTER TABLE OBJECT_REFERENCE ALTER COLUMN SYSTEM_INSTANCE DROP NOT NULL;
+
+ALTER TABLE TASK ALTER COLUMN POR_SYSTEM DROP NOT NULL;
+ALTER TABLE TASK ALTER COLUMN POR_INSTANCE DROP NOT NULL;
 
-ALTER TABLE TASK ALTER COLUMN POR_SYSTEM SET NULL;
-ALTER TABLE TASK ALTER COLUMN POR_SYSTEM_INSTANCE SET NULL;