Oracle Water for Oracle in the preliminary interview

I don't know how much you know about Oracle? is not just to reach the level of use. If so, follow my steps to get to know Oracle and slowly uncover the mysteries of Oracle.

For the installation of Oracle, here I do not want to say, the tutorial online search a lot of, what 10g 11g, go to search, more is. At the beginning of the article, we do not cut to the point, may wish to start from after installation. After Oracle is installed, two users are automatically generated, as the one who knows a little bit about Oracle, one is SYS and one is system. Perhaps you only know that these two are database default users and have very high permissions. So how high is the specific authority? Let you say how much you can tell. For us, just a little bit about these two special users.

First of all, Sys is a superuser, with the highest privileges and the SYSDBA role, what is the SYSDBA role? That's a long way to go. We also have to say that this sysdba is logged in as SYSDBA, speaking of identity, Oracle has three kinds of identities, one is normal identity, we have authorized the user often as normal login ; One is SYSDBA system administrator login; The last one is Sysoper is the system operator identity. Let's go back. SYS, which has the highest permissions, has the CREATE DATABASE permission, the user's default password is Change_on_install. Oh, a bit long ha. Later I will say how to change its password. Next introduce system, this needless to say, all know is the system administrator, its permissions are also very large, with sysoper role, above said, is the system operator identity, no CREATE DATABASE permissions, the default password is the manager. Oh, this password is relatively good to remember. So next, let's introduce how to change the user's password.

When are we going to change the code? Usually our QQ, and so on, either the password is too long, or the password forgotten, will want to change the password. Oracle inside the same user, like the above sys, the default password is so long, change_on_install, I guess you must have the impulse to change, then how do you alter the password? Don't worry, look here.

1. Enter sqlplus/nolog on the command line no user name login

2. Conn/as SYSDBA connect to local database

3, ALTER USER * * * (you want to change the username, such as system) identified by * * * (you want to change into the password);

For example: Alter user system identified by abc123; Remember! You must add a semicolon after the statement!

Well, here we end this blog, which is a simple way to get started with Oracle, next blog Let's say how to use Navicat to connect to an Oracle database. See the next blog post.

Oracle Water for Oracle in the preliminary interview