one,
When mysql is installing the server, the root user is specified, and then logging in to root can create multiple databases in navicat (equivalent to oracle's schema)
Oracle can create multiple database instances on the server side, and specify the passwords of system and sys, and then create a user (schema), and then you can imp dmp under the user, or create a table.
And you can see that the schema in hibernate-mapping: In Oracle, it is the user, and in MySQL, it refers to the database.
two,
clob: There is no such type in mysql, but only in db2/oracle, but in mysql it can be replaced with text or varchar, which is actually equivalent to String.
blob: This type exists in mysql and is equivalent to a byte array.
text: When MySQL 5.0.3 or below, data with a length of more than 255 bytes can be stored. At that time, varchar can only store data with a length of 255 bytes.
After 5.0.3, varchar can store a maximum length of 65535, and text and varchar are almost the same.