diff -up src/sage/databases/cremona.py.orig src/sage/databases/cremona.py
--- src/sage/databases/cremona.py.orig	2019-10-03 14:57:32.516349793 -0300
+++ src/sage/databases/cremona.py	2019-10-03 14:57:45.084423307 -0300
@@ -850,7 +850,8 @@ class MiniCremonaDatabase(SQLDatabase):
                 message = "There is no elliptic curve with label " \
                     + label + " in the default database; try installing " \
                     + "the optional package database_cremona_ellcurve which " \
-                    + "contains the complete Cremona database"
+                    + "contains the complete Cremona database: " \
+                    + "sudo dnf install sagemath-data-elliptic_curves_large"
             raise ValueError(message)
         ainvs = eval(c[0])
         data = {'cremona_label': label,
@@ -1649,6 +1650,7 @@ class LargeCremonaDatabase(MiniCremonaDa
             con.executemany("UPDATE t_curve SET gens=? WHERE curve=?", \
                 curve_data)
             print("Committing...")
+            self.commit()
             if largest_conductor and int(v[0]) > largest_conductor: break