@arjun more What we wanted to say is ... that the "NULL" value is how it is shown for MySQL. Other databases like PostgreSQL might show that NULL column value as blank. So as you are using MySQL so the NULL value is fine there (until there is a upgrade already going on) ... Otherwise the value for that column in MYSQL can be seen as NULL. So your Database shows correct value if there is no upgrade initiated. NULL is not same as blank string. So your update query is Incorrect where you are trying to set a blank string value there. For Example: in Postgres same value you can see as blank (Empty) but actually that is NULL # psql -U ambari ambari
Password for user ambari:
psql (9.2.18)
Type "help" for help.
ambari=> SELECT cluster_id , resource_id , upgrade_id , cluster_info , cluster_name, provisioning_state FROM clusters;
cluster_id | resource_id | upgrade_id | cluster_info | cluster_name | provisioning_state
------------+-------------+------------+--------------+--------------+--------------------
2 | 4 | | | plain_ambari | INSTALLED
<br> . Similar Table on MySQL is shown as following with NULL value: mysql> SELECT cluster_id , resource_id , upgrade_id , cluster_info , cluster_name, provisioning_state FROM clusters;
+------------+-------------+------------+--------------+--------------+--------------------+
| cluster_id | resource_id | upgrade_id | cluster_info | cluster_name | provisioning_state |
+------------+-------------+------------+--------------+--------------+--------------------+
| 2 | 4 | NULL | | plain | INSTALLED |
+------------+-------------+------------+--------------+--------------+--------------------+ The Main Question here is "Why do you want to set the value of that column to blank String" ? It is already NULL.
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