Oracle Database FAQ

/* Login/*

c:>sqlplus/nolog;

...
Sql> conn/as sysdba (Local database)
sql> conn user/passwd  ; (Switch User)

/* Create an empty table with the same table column name and type as already exists.

CREATE TABLE Table_bak

As SELECT * FROM table where 1<>1;

* * Resolve ora-28001 The password has expired problem

1, login with SYSDBA user

2, view account information, select Username,account_status from Dba_users;

3, if the account is locked/expired first unlock

Alter user USERNAME account unlock;

Change Password again:

Alter user USERNAME identified by NewPassword;

/*oracle Example * *

Oracle's running structure is: Operating system-->oracle Program--> instance, that is, an operating system can create multiple instances, each instance has its own memory structure and process scheduling, so not exactly the same as SQL Server.
Default instance: Oracle will create a ORCL instance when choosing a default installation

/* Create sequence * *

Create sequence sequence name increment by 1 start with 100;

/* Delete sequence * *
Drop sequence sequence name;

/* Modify the table name * *

Rename TableName to tablename1;

/* Delete the primary key of the table * *
ALTER TABLE name drop constraint primary key name;