About Oracle (1)

The installation is very simple. You can enter the next path or enter the path. What is the secret of the account? Google is not enough...
It takes a long time to install it on my broken machine... you can create an initial database during installation, and several account secrets are important during installation, that is, the default accounts of the system...
System is the default sysdba permission user. Scott is the user you used to practice.
At the same time, it seems that sys is also the default account. At the same time, he can use sysdba sysopen normal three permissions to log on. It seems that this user has too many details. Otherwise, I will become a DBA and Google it if I have time.
Sysdba sysopen normal is the identity when the database is connected. sysdba can start or close the database and perform other operations normally.
By the way, it seems like the first installation and creation of the default database. Once the database is built, it seems that many default users are locked. You need to unlock the database and reset the password, such as the famous Scott...

Let's review Oracle basics later.
1. system services
Go to the Windows System Service Management page, and sort by name. You will find several major ORACLE data items. If this is the first installation, there will be oracleoradb10g_hometnslistener oracleoradb10g_homeisql * Plus [oraclejobschedulerorcl, oracleserviceorcl] these two special features are mentioned later. In fact, this is the first time if two services corresponding to the database with the initial database name are created, this is the strange local database instance in Oracle that is enabled in the form of system services, the first two are the so-called TNS Listener service. The last one is the so-called B/s SQL * Plus...
2. configuration files and System Directories
First, many...
There are a lot more...
These two brothers must be introduced together.
ORACLE_HOME
This is the installation directory of your Oracle.
Oradata directory
This is the default storage location for each Oracle database instance. Of course, you can change it to your favorite place. It is nothing more than the data storage file control file redo log file. What table space files are there? And so on
Flash_recovery_area directory
Do you know the babybox files? That is, you can use it to return to your database.
Admin directory
This seems like admin, but admin doesn't know much at present. It seems that every database instance has a corresponding folder below.
DB directory
This is a big topic. I would like to pick a few people who will be familiar with the introduction.
DB/Admin directory
Dumb... a sample in it looks like admin outside, but it's empty at present...
DB/bin directory
A lot of EXE bat, many command line related stuff are added to the path. Don't tell me "What is path ..."
DB/database directory
The database instance startup parameter file is named init <Sid>. ora Sid is the unique name of the database instance you created. Of course, the database instance name is best in the form of domain name. It seems that the content in this file is too broad. A lot of startup parameters can be changed, and it seems that there is another the content points to the spfile path. Later I will talk about it. I can only say that the parameters that can be modified to start the database instance are divided into static modification and dynamic modification. There are alter session and alter system. It seems that the previous one can only modify and restart the instance dynamically. expired. at the same time, there is a confusing concept here. Dynamic Modification and static modification of startup parameters dynamic support for instance changes at runtime will immediately take effect and restart will expire, but it also means that the restart will not expire... static modification also refers to directly modifying the parameters in the configuration file... in fact, it is mainly about alter system, which obfuscated the concept. He can specify the memory spfile and both parameters. That is to say, he can think that it will only take effect immediately after the runtime, but it will also take effect immediately. do not modify the parameter configuration file. For details, some sub-parameters can be modified... by the way, the Administration Assistant for windows in [configuration and porting tools] can modify this startup parameter and specify that the default instance Sid is mainly the node in the Oracle Home directory in the right-click... watch it for yourself
DB/DBS directory
The so-called static startup parameter is here... each instance has a name spfile <Sid>. ora
DB/jdbc directory
Java driver here... jdk1.2 1.3please use classes12.jaror classes12.zip 1.4 or above. Please use ojdbc14.jar. They are not clear in Lib. Please refer to readme.txt for instructions in this directory...
DB/network directory
Important
The admin in this example is relatively powerful.
Listener. the ora file mainly configures the port of the local database service listening mode... please use [configuration and porting tools]. net manager for convenience. Manual modification must be noted. Otherwise, it will not take effect. I will not repeat this issue later. If it cannot be connected, especially remote connection to your machine. if you do not need to check the configuration of this file, check the default host = your machine name. If your host cannot be pinged, it is recommended to change the host file or directly use the IP address. [configure and port the tool here. ]. Net configuration assistant changed this more powerful Query type, but I still haven't changed it.
What are the main access policy Connection Methods of the sqlnet. ora file?
Database instance service name instance running mode I wonder if changing the service name will affect the Windows System Service name I have not tried
Tnsnames. the ora file determines that you cannot connect to others, and whether others can connect to you. You can define the connection mode of the database instance. However, if you are still another user, this file must reflect the instance running mode. We recommend using sharing. if there are more than one, you will not be able to see an oracle process in each instance with a memory space of more than 200 MB. You can use the [configuration and porting tool] net configuration assistant Wizard to change the configuration or Google
The [configuration and migration tool]. Net configuration assistant configuration is easy to use.
The directory ends here...
Then I'm sure I want to connect to the default database. Please use the built-in sqlplus. No matter the client or the command line, remember that some default accounts locked will not be able to use the system. You must specify the permissions to connect to sysdba or sysopen. it is convenient to use the account/password @ database instance (generally TNS name) for the client to specify a role) as role (such as sysdba sysopen), of course, the command line can also be like this.
This can be a mess.
Talk about it later ....