fix for incorrect lastrowid

Author: daimor

sqlalchemy_iris/base.py

@@ -468,7 +468,9 @@ def get_column_specification(self, column, **kwargs):
             column.primary_key
             and column is column.table._autoincrement_column
         ):
-            colspec.append("SERIAL")
+            # colspec.append("SERIAL")
+            # IDENTITY and ALLOWIDENTITYINSERT = 1 in table instead of SERIAL to solve issue with LAST_IDENTITY()
+            colspec.append("IDENTITY")
         else:
             colspec.append(
                 self.dialect.type_compiler.process(
@@ -494,6 +496,9 @@ def get_column_specification(self, column, **kwargs):
 
         return " ".join(colspec)
 
+    def post_create_table(self, table):
+        return " WITH %%CLASSPARAMETER ALLOWIDENTITYINSERT = 1"
+
 
 class IRISTypeCompiler(compiler.GenericTypeCompiler):
     def visit_boolean(self, type_, **kw):