Shulou(Shulou.com)06/01 Report--

These days the company does database migration, from the original oracle database to mysql database, there is a strange problem.

After the data source was changed to mysql, there was a problem of [java.sql.SQLException: No tables used], which perplexed me for four or five days.

No problem with database connection, no problem with jar package, no problem with mapping file. I don't know how this anomaly came into being. I look up the information on the Internet, and there is basically no information about this anomaly. Now we finally find out why.

Originally, when configuring the hibernate data source, there was a test sql [SELECT * FROM DUAL], but this statement only applies to the oracle database. If the mysql database does not work, it has to be changed to [SELECT 1 FROM DUAL] and solved.

Or characters should be in single quotation marks: SELECT'* 'FROM DUAL

Hibernate+mysql must pay attention to this.

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