Oracle

Many application scenarios, in order to prevent the occurrence of disasters, to protect against the loss of important data, remote disaster recovery solution level is not poor. Then the database will undoubtedly become the focus of the protection of

Create userCreate user username identified by password default tablespace temporary tablespace temporary table space;View table Space SizeSelect Tablespace_name, sum (bytes)/1024/1024 from Dba_data_files Group by Tablespace_name;View table space and

Statement:ALTER TABLE tableName Rename column oldcname to Newcname; --Modify field namesALTER TABLE TableName Modify (cloumnname data type); --Modifying data typesFor example:1. Create a table:CREATE TABLE Student (ID VARCHAR2 (+) primary key,Name

1 DML (Data manipulation language) data manipulation Language2 for adding, deleting, and changing data in a database3Often accompanied by Tcl (things operating language)----commit (save); rollback (rollback);4 Create TableStu (ID Number(5),

Early use of Linux, look at the Oracle listening state and port is just a glance, did not seriously read the content is also the English hint, a few load new pick up Oracle,WinDOS cmd to view listening status find lots of interesting questions,

Oracle executes external files:C:>sqlplus user/[email protected]sql> @new. sqlExecute multiple SQL files:1. Place all the files in the same directory and execute the command at the command line:c:>dir/b > D:/1.sqlAll the SQL file names are exported

--View the single table structure of an Oracle databaseSelect Dbms_metadata.get_ddl (' TABLE ', ' table_name ') from dual;There are two parameters in parentheses, the first parameter is the object we want to query, here is the table structure, so it

Oracle Import failed, the length of the ORA-12899, is the character set caused by the Chinese in the UTF-8 accounted for 3 bytes, zhs16gbk accounted for 2 bytes, and the source DMP file character set is ZHS16GBK the data poured out of the

Primary users and their roles in Oracle databases No. User name Default password Describe 1 Sys Change_on_install Super Administrator of the database 2 System Manager

Common versions of Oracle databases In the development of Oracle database, the database has been in a state of continuous upgrade, with the following versions: Oracle 8,oracle 8i:oracle 8i means Oracle is formally evolving to the

1--1. Creating a Test Table 2 CREATE TABLE job_test (ID integer,add_time date); 3 4--2. Creating a Stored procedure5 Create or Replace procedurePrc_job_test is 6 begin 7 Insert intoJob_testValues(Seq_tm_id.nextval, sysdate); 8 Commit; 9

Installing Oracle-database-server-12cr2-preinstallwget http://public-yum.oracle.com/public-yum-ol7.repo -O /etc/yum.repos.d/public-yum-ol7.repowget http://public-yum.oracle.com/RPM-GPG-KEY-oracle-ol7 -O /etc/pki/rpm-gpg/RPM-GPG-KEY-oracleyum clean

--To view the maximum number of connections to a databaseSelectValue fromV$parameterwhereName ='Processes';--change the number of database connectionsAlter systemSetprocesses = theScope =SPFile;--to view locked

View database Character Set encodingSelect USEREVN (' language ') from dual;Oracle Common functions:LOWER (' AAAAA '), convert all characters to lowercaseUPPER (' aaaaasss ') to convert all characters to uppercaseInitcap (' Atsichuan Chengdu '),

--Each month in the time period, {0}: Start date, {1}: End Date Select To_char (Add_months (To_date ('{0}','yyyy-mm'), ROWNUM-1), 'yyyymm'As monthlist from DUAL CONNECT by ROWNUMMonths_between (To_date ('{1}','yyyy-mm'), To_

table spaces and data files1. Tablespace is a disk logical space for a database.2. Each table space consists of one or more data files.3. A data file can only belong to one table space.After completing the Oracle system installation and creating an

Relationship between PDB, CDB, and users in Oracle12c, oracle12cpdb CDB: CDB is called the Container Database and the Container Database. (Public users) PDB: PDB is called Pluggable Database, which is Pluggable. (Local User) Link example: We

Oracle database instances and servicesA. instances and databases 1. instance: A group of Oracle background processes/threads andShared Memory ZoneThe memory is shared by threads/processes running on the same computer. An instance is used to manage

Quick oracle shutdown and enabling for Batch Processing Since oracle accounts for a large amount of memory, we usually convert auto-start to manual start. Find the managed services and the services in the application on the computer, and change

Oracle where condition execution sequence analysis 1, oraclewhere (1) execution sequence of statement ParsingCreate a function for testingCreate or replace function F1 (v_in in varchar2)Return varchar2 ISV_out varchar2 (20 );BeginV_out: =