Oracle

************************************************************************* * * * Original:blog.csdn.net/clark_xu Xu Changliang's Column************************************************************************Description of the problem:Original SGA 4G.

Python can operate on an Oracle database by using the Cx_oracle module.First, you need to download the Cx_oracle module: HTTPS://PYPI.PYTHON.ORG/PYPI/CX_ORACLE/6.0RC1Note the version when downloading, against the Python version and the number of

Small series often encountered "error" when using OracleORA-12541:TNS: No listener ""Multi-party search, find a good solution, to share with you: 1Open "Oracle Net configuration Assistance" from the Start menu, select "Listener Configuration"

------------------------------------------------------------------Find out the EMP tableSELECT * from EMP;--Select all information for employees in department 30SELECT * from emp where deptno = 30;--The number of the employee who listed the position

--The following are the related tablesSELECT * from V$lock;SELECT * from V$sqlarea;SELECT * from V$session;SELECT * from V$process;SELECT * from V$locked_object;SELECT * from All_objects;SELECT * from v$session_wait;--View the locked tableSelect

Select * fromEmp--All data in EMP tableSelect * fromEmpwhereEnameinch('SMITH')--The data where ename is snith in the EMP tableSelectEname||'Is a' asIname fromEmpwhereEname= 'SMITH'--rename Ename Pius ' is a ' to InameSelectSal|| '_'||Ename

0. The Scott User default table describesScott user tables directory contains four tables1. Insert (INSERT) statementTo insert data into a specified column:Insert into Values ("xx");Insert all column data:Insert into Values (x,'xx','lll');2.

sql>startup;Sql> select * from V$version; View version numberSql> SELECT * from dba_profiles s WHERE s.profile= ' DEFAULT ' and resource_name= ' password_life_time '; View password expiration settings for a specified profile (such as default)Sql>

What the database can't avoid is processing the dataScenario: Invoice information, many company employees in the transaction, fill in the invoice information is the same, so the company employees often want to call the unified invoice information,

In the high concurrency database system, the cache of sequences should be adjusted correspondingly. Now look at the definition of a high-concurrency sequence of the database itself. When we send a request to the database, listen to the reception,

In Oracle 11g, Oracle added 2 queries: Pivot (row to column) and Unpivot (column change)Pivot (aggregate function for column name in (type)), where in (") you can specify an alias, in, you can also specify a subqueryRow to column:SELECT * from

1. Oracle is a large database and MySQL is a small and medium-sized database, Oracle has a market share of only about 20% 40%,mysql, while MySQL is open source and Oracle is very expensive.2. Oracle supports high concurrency, large traffic, and is

Create Public database link Link_mm_devConnect to STL identified by FosssitUsing ' (DESCRIPTION =(Address_list =(ADDRESS = (PROTOCOL = TCP) (HOST = 192.168.10.111) (PORT = 1521)))(Connect_data =(service_name = FOSSDBSB)))‘;--1 Link_mm_dev dblink

1. Oracle Naming conventions:1. Strictly case-sensitive 2. All SQL statements must be '; ' End 3. All SQL is separated by a space: Sqlplus space/space as space SYSDBA enter 4. Both the table name and the list must start with a letter the class in

One of the biggest headaches is having a primary key problem when inserting data into a table.Since the primary key cannot be repeated, you have to define a rule by itself to generate a value assigned to the primary key without repeating it.Now it's

The merge into statement is a new syntax for merging update and INSERT statements in oracle9i.Through the merge statement, the other table is queried based on the join criteria of a single table or multi-table union query, and an update on the join

This article copyright belongs to the distant wind Lyh and the blog garden altogether, welcome reprint, but must retain this paragraph statement, and gives the original text link, thanks cooperation.Since I have been using MySQL for some of the

The Oracle database can run in 2 modes: Archive Mode (Archivelog) Archiving mode can improve the recoverability of Oracle database, the production database should run in this mode, the archiving mode should be combined with the

---a single index reset statementAlter index INDEXNAME rebuild;---Querying Data Index object statementsSELECT * from User_indexes;------The index of the database (the index containing the $ character cannot be rebuilt) bulk generate index Reset

Notice several small details of Oracle database installation at 12c Release 2 Oui, which are recorded as follows:1. In the DBCA Wizard, it is specified by default to create a ORCL CDB database and a orclpdb pluggable database. In the previous