Oracle function summary, oracle Summary

Oracle function summary, oracle Summary

Among the various databases that are currently popular, why oracle can be listed at the beginning and the birth of oracle has brought a storm to the use of the whole database, what functions and advantages does oracle have?

What are the advantages of functional modules in Oracle?
1. Oracle has better stability than SQL Server.

The sqlload.exe function of oracle is better than the Bcp function of SQL Server. oracle can import text data according to the conditions.

III. The security mechanism of Oracle is better than that of SqlServer.

4. Oracle has a powerful operating mechanism in the big data processing module.

5. Fast data processing.

Use of various development tools
1. PL/SQL Developer
Compared with developers, the interface is easy to use and has many functions.

Ii. Todd
Professional users can use DBA, Which is powerful and easy to use. Due to time problems, the actual use of DBA is gradually decreasing.

Sqlplus logon methods

Sqlplus has several login methods, such:
1. C:> sqlplus/as sysdba;-log on to the oracle sys administrator authorized by the operating system
2. C:> sqlplus/nolog-Logon mode where the password is not exposed in cmd or terminal
SQL> conn/as sysdba
Or
SQL> conn sys/password as sysdba
3. C:> sqlplus scott/tiger-non-administrator user login
4. C:> sqlplus scott/tiger @ orcl-non-administrator users use the tns alias to log on
5. C:> sqlplus sys/password @ orcl as sysdba-the Administrator uses the tns alias to log on.
6. C:> sqlplus-Logon without revealing a password
Enter user-name: sys
Enter password: password as sysdba-The as sysdba clause must be added to Log On as sysdba as a sys user.

Note:
We recommend that you use the Logon account name and password
Scott/tiger
System/manager
Sys/change_on_install
Hr/hr
And so on.

Common numeric dictionary
All tests performed by Oracle SQL Developer on Oracle 11g R1 passed. Many data dictionaries must be logged on as system or sysdba.

--- Desc v $ instance; select * from v $ instance; -- desc v $ datafile; select * from v $ datafile; desc dba_data_files; select file_name, file_id, tablespace_name, bytes, blocks, status, online_status from dba_data_files; -- basic information about temporary files desc dba_temp_files; select file_name, file_id, tablespace_name, status, bytes/1024/1024 MB from dba_temp_files; -- Basic information of the control file desc v $ controlfile; select name, status, is_recovery_dest_file, block_size, file_size_blks from v $ controlfile; -- desc v $ logfile; select group #, status, type, member, is_recovery_dest_file from v $ logfile; -- desc v $ database; select * from v $ database; select dbid, name, created, login, log_mode, open_mode, checkpoint_change #, Region #, controlfile_created, controlfile_type, controlfile_sequence #, controlfile_change #, controlfile_time, protection_mode, database_role from v $ database; -- log file parameter information show parameter log_archive_dest; -- access parameter file desc v $ parameter; select num, name, type, value, display_value, isdefault, isses_modifiable, issys_modifiable, isinstance_modifiable from v $ parameter; select * from v $ parameter; select name, value, description from v $ parameter; -- background process information desc v $ bgprocess; select paddr, pserial #, name, description, error from v $ bgprocess; -- desc dba_tables; desc dba_tab_columns; select owner, table_name, column_name, data_type, data_length, global_stats, data_upgraded, histogram from dba_tab_columns; -- desc dba_views, select owner, view_name, read_only from dba_views; -- desc dba_synonyms; select owner, synonym_name, table_owner, table_name, db_link from dba_synonyms; -- desc dba_sequences for all sequences of DBA users; select sequence_owner, sequence_name, min_value, max_value, cycle_flag from dba_sequences; -- desc constraints for all DBA user constraints; select owner, constraint_name, constraint_type, table_name, status from limit; -- desc dba_indexes, which is the basic information of all the indexes of DBA users; select owner, index_name, index_type, table_owner, table_name, table_type, uniqueness, compression, logging, status from dba_indexes; -- desc dba_triggers, select owner, trigger_name, trigger_type, table_owner, table_name, column_name from dba_triggers; -- desc dba_source, which is the basic information of all stored procedures of DBA users; select owner, name, type, line, text from dba_source; -- desc dba_segments, which is the basic information of all the segments of DBA users; select owner, segment_name, segment_type, tablespace_name, blocks, extents from dba_segments; -- desc revoke select owner, segment_name, region, tablespace_name, extent_id, file_id, blocks from dba_extents; -- desc dba_objects, basic information of all DBA objects; select owner, object_name, subobject_name, object_id, data_object_id, object_type, created, status, namespace from dba_objects; -- All base tables that the current user can access: desc cat; select table_name from cat; -- all base tables, views, and synonyms that the current user can access: desc system. tab; select tname, tabtype, clusterid from system. tab; -- desc dict, which constitutes all the table information of the data dictionary; select table_name, comments from dict; -- Query some basic data dictionaries about the tablespace desc dba_tablespaces; select tablespace_name, block_size, status, logging, extent_management from dba_tablespaces; desc dba_free_space; select tablespace_name, file_id, block_id, bytes/1024/1024 MB in size, blocks, relative_fno from dba_free_space; -- some basic information about the archive status: desc v $ archived_log; select name, dest_id, blocks, block_size, archived, status, backup_count from v $ archived_log; -- some information about the memory structure: desc v $ sga; select name, value/1024/1024 MB from v $ sga; desc v $ sgastat; select pool, name, bytes from v $ sgastat; desc v $ db_object_cache; select owner, name, db_link, type, namespace, locks from v $ db_object_cache; desc v $ SQL; select SQL _text, SQL _id, cpu_time from v $ SQL;

Various data files in Oracle
I. Data File)
Each table space in Oracle Data is composed of one or more physical data files.

2. Controlfile)
A control file is a binary file used for database startup and normal operation.

When the database is running, the control file is frequently modified by Oracle. Therefore, when the database is in the open state, the control file must be writable. If the control file cannot be accessed for some reason, the database will not work properly.
　　
Control file) will be updated to reflect the physical structure changes of these databases.

3. redo log files
Oracle introduces redo logs for database restoration.
Oracle-related processes: redo the log write process (LGWR ).
Redo log properties: Online log files, which need to be managed when running oracle servers.
Related numeric dictionary: v Log; v Logfile.
Operator permission: You have sys or system user permissions.

Iv. archiving log files
Archive Log is a non-active backup of redo logs. archive logs can be used to keep all redo history records. When the database is in ARCHIVELOG mode and the log is switched, the background process ARCH will save the redo log content to the archive log. when a media failure occurs in the database, you can use data file backup, archive logs and redo logs to completely restore the database.