Database name (DB_NAME), database instance name (Instance_name, ORACLE_SID), the domain name database, the global database name, database service name
only database name (db_name) and database instance name (instance_name) in ORACLE7,8 database.
In ORACLE8i, 9i in the emergence of new parameters, namely the database domain name (db_domain), service name (service_name), and the operating system environment variables (ORACLE_SID).
First, what is the database name (db_name)?
Database name is used to distinguish internal identification data is then stored in a binary parameter database control file, install or create the data will not be modified.
After installation is complete database, the parameters are written to the database pfile parameter file in the following format:
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.........
db_name = "ORCL" # (not modify)
db_domain = dbcenter. toys.com
instance_name = ORCL
SERVICE_NAMES = orcl.dbcenter.toys.com
the control_file = (...............
.........
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In ORACLE8i each database running in both a database name (db_name), if a server program creates two databases, there are two database name.
Which it belongs to the control parameter data associated with the control of the pfile different databases.
The name of the current database query
method: the SELECT name from v $ Database;
SQL> name from the SELECT v $ Database;
NAME
---------
ORCL
Method Two: Show the Parameter db
SQL> --db_name database name, db_domain database domain name
SQL> Show the Parameter db
NAME the TYPE of VALUE
------------------------------------ ----- ------------------------------ ------
db_16k_cache_size Big Integer 0
db_2k_cache_size Big Integer 0
db_32k_cache_size big integer 0
db_4k_cache_size big integer 0
db_8k_cache_size big integer 0
db_block_buffers integer 0
db_block_checking string FALSE
db_block_checksum string TRUE
db_block_size integer 8192
db_cache_advice string ON
db_cache_size big integer 0
db_create_file_dest string
db_create_online_log_dest_1 string
db_create_online_log_dest_2 string
db_create_online_log_dest_3 string
db_create_online_log_dest_4 string
db_create_online_log_dest_5 string
db_domain string
db_file_multiblock_read_count integer 16
db_file_name_convert string
db_files integer 200
db_flashback_retention_target integer 1440
db_keep_cache_size big integer 0
db_name string orcl
db_recovery_file_dest string c:/oracle/product/10.2.0/flash_recovery_area
db_recovery_file_dest_size big integer 2G
db_recycle_cache_size big integer 0
db_unique_name string orcl
db_writer_processes integer 1
dbwr_io_slaves integer 0
rdbms_server_dn string
standby_archive_dest string %ORACLE_HOME%/RDBMS
standby_file_management string MANUAL
SQL> select value from v$parameter where name='db_name';
VALUE
-------------------------------------------------- ------
orcl
method three: View the parameter file.
Second, what is the database instance name (instance_name, ORACLE_SID)
is sometimes used instance name (instance_name) parameters for the description of the database instance name, sometimes used ORACLE_SID parameter. These are two examples of the database, as shown below differences:
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(the ORACLE_SID)
the OS <----------------> the ORACLE database <----- --- (instance_name (instance name))
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the figure shows the relationship between the instance name instance_name, ORACLE_SID database and operating systems,
instance_name ORACLE database parameter is a parameter, this parameter in the parameter file can be the query, when using the external connection.
After e.g., to a database server, and a connection, it is necessary to know the instance_name, only know the name of the database is of no use, as the database name, or installation data to create the database,
instance name can be modified. After installation is complete database, the name of the instance is written to the database pfile parameter file in the following format:
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db_name = "orcl" # (not modify)
db_domain = dbcenter.toys.com
instance_name ORCL = # (can be modified, may be the same or different db_name)
SERVICE_NAMES = orcl.dbcenter.toys.com
the control_file = (.... ...........
.........
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query the current database instance name
method one: the SELECT instance_name from v $ instance;
SQL> the SELECT instance_name from v $ instance;
INSTANCE_NAME
----------------
ORCL
method two: Parameter instance Show
the SQL> Show Parameter instance;
NAME the TYPE of VALUE
------------------------------------ ----------- ---------
active_instance_count integer
cluster_database_instances integer 1
instance_groups string
instance_name string orcl
instance_number integer 0
instance_type string RDBMS
open_links_per_instance integer 4
parallel_instance_group string
parallel_server_instances integer 1
SQL> select value from v$parameter where name='instance_name';
Of VALUE
------------------------------------------------- -------------
orcl
method three: query in the parameter file.
The ORACLE_SID parameter is the operating system environment variables, and for operating system interaction. That is, in order to get the operating system instance name, you must use ORACLE_SID. This parameter ORACLE_BASE, ORACLE_HOME, etc. the same usage.
After database installation, ORACLE_SID is used to define the name of the database parameter file. Such as:
$ ORACLE_BASE / ADMIN / DB_NAME / pfile / the init $ ORACLE_SID.ora.
The method defined:
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Export the ORACLE_SID = ORCL
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If multiple databases created in the same server, the same time there must be a plurality of database instances, then the process can repeat as defined above, to select a different instance.
Can also use
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[Oracle @ Datacent] $ the oraenv.
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To switch to a different start ORACLE_SID different instances (instance) through the operating system
ORACLE_SID connected to the network
ORACLE_SID oracle server is further configured to identify the network connection. When configuring the oracle host connection string, it is necessary to specify ORACLE_SID.
Of course, after the 8i version of the network components requires the use of a service name SERVICE_NAMES. This concept is explained next.
Third, the relationship between the database name and instance name.
The relationship between the database name and the instance name is generally one to one relationship, there is a name there is a database instance name,
if you create two databases on a single server, there are two database name, database instance name two, with determining a two identification database, the user is connected, and examples.
However, 8i, 9i parallel server architecture (i.e. oracle real application cluster), the database instance between many relationship, (corresponding to a plurality of database instances, a user only one time instance linked, when a certain examples of failure, other examples of automated services to ensure the safe operation of the database.)
Fourth, what is the database domain name?
In the distributed database system work, between different versions of the database server, regardless of the operating system is running unix or windows, can be remote replication through a database link between the server and
database domain name primarily for the oracle in a distributed environment replication. An example:
distributed database system of the National Traffic transportation administration, including:
Fujian node: fj.jtyz
Xiamen, Fujian node: xm.fj.jtyz
Jiangxi: jx.jtyz
Jiangxi Shangrao: sr.jx.jtyz
This is the domain name database.
Database domain names exist in the parameter file, his argument is db_domain.
Query the database domain
method: the SELECT value from v $ the Parameter the WHERE name = 'db_domain';
SQL> the SELECT value from v $ the Parameter the WHERE name = 'db_domain';
of VALUE
-------------------------------------------------- ---------
method two: Show the Parameter Domain
SQL> Show the Parameter Domain
NAME the TYPE of VALUE
--------------------------- --------- ----------- ------------------
db_domain String
method three: query in the parameter file.
Fifth, the global database name
Global database name = name + database domain database, such as the aforementioned global database name is Fujian node: oradb.fj.jtyz
Six, what is the database service name?
From oracle9i version, we introduced a new parameter, the database service name. Parameter name is SERVICE_NAMES.
If you have a domain name database, the database service name is the global database name; otherwise, the database server name and database name the same.
Query the database service name
Method One: the SELECT value from v $ the Parameter the WHERE name = 'SERVICE_NAMES';
SQL> value from the SELECT v $ the Parameter the WHERE name = 'SERVICE_NAMES';
of VALUE
-------------- ------------------------------------------------
orcl
method two: Show the Parameter service_name
SQL> Show the Parameter service_name;
NAME the TYPE of VALUE
------------------------------------ ----------- ---------
service_names string orcl
Method three: Query in the parameter file.
Database services connected to the network
oracle network components oracle8i from the beginning of the database and the client host connection string using the database service name. Before using a ORACLE_SID, namely database instance name
