Oracle

I. Oracle monitoring exception1. Check whether the Oracle database is started: Ps-ef | grep ora2. Check whether the Oracle database listener is started: Ps-ef | grep LISTEN3. Check if the Oracle DB Listener is healthy: lsnrctl statusIf not started,

1. Create a tableCreate Tabletest01 (IDint not NULL Primary Key, namevarchar(8) not NULL, Gendervarchar2(2) not NULL, Ageint not NULL, Addressvarchar2( -)default' Address Unknown ' not NULL, Regdata date);Constraintsnonempty constraint NOT

1. Oracle DatabaseCharge database, strong data processing capability, high security2. The language of the operating databaseSQL language, the standard of execution is the SQL99 standard3. Products of the database① charges: Oracle, SQL Server, DB2 ...

Reason one Oracle generates ROWMUN,ROWID fields for each table by default, and these fields we call pseudo-columns1 Creating a Test tableCREATE TABLE TEST (ID number,name VARCHAR2 (20))2 Inserting test dataINSERT into test values (1, ' Zhang San ');

Single-Table query:　　1. mix with OR and andRequirements: Query owner name contains ' Liu ' or house number containing ' 5 ', and Address No. 3 recordSELECT * from WHERE like ' % LIU% ' or like ' %5% ' and = 3and permissions take precedence over

Statement recursively finds parent-child relationship statementsTable structure and data1. Traversing a child node through the root nodeSelect T.*,level from Test2 t START with T.parentid=0 CONNECT by PRIOR t.id = T.parentid2. Tracing through the

Move control Files[[email protected] ~]$ Sqlplus/as sysdbasql> set line 200sql> col name to a60sql> select Status,name from V$co Ntrolfile;                      STATUS NAME------------------------------------------------------------------------------

The Oracle with statement can implement the same sequence as the Connect by statement:Connect by usageUse RowNum to implement a sequence of 1 to 10.Select RowNum from dual connect by rownumUse the level to achieve a sequence of 1 to 10.Select level

OS boot Ohasd1,exec /etc/init.d/init.ohasd run >/dev/null 2>&1 /dev/null 2>&1 .vip,ora.scan.vip                                oraagent_grid: Start the ora.asm,ora..lsnr,ora..lsnroraagent_oracle: Start ora..db,ora..svcOracle Grid Infrastructure

1. An implicit conversion causes an index to fail. This should be taken seriously. It is also a common mistake in development.Because the table's field TU_MDN is defined as VARCHAR2 (20), the field is passed to Oracle as the number type in the query,

Install the corresponding Oracle client (Instant clients) according to the Python version and the database version:http://www.oracle.com/technetwork/database/database-technologies/instant-client/downloads/index.htmlDepending on the version of Plsql,

First, the basic type of data　　1. Pseudo-Columns of Oracle　　　　A pseudo-column in Oracle is like a table column, but it is not stored in a table where pseudo-columns can be queried from a table, but cannot be inserted, updated, and deleted by their

Version alternationhttp://www.sohu.com/a/163264045_505827The next version of Oracle database will be Oracle 18.ObjectiveIn order to faster, through the annual release of the new features to the user, small steps to run, grayscale publishing, you can

Sometimes we query Gv$sql to see some running details for the same SQL different child cursors:Selet T.inst_id,t.sql_id,t.child_number,t.plan_hash_value,t.last_active_time,t.elapsed_time/100000/decode ( t.executions,0,1,t.executions), t.elapsed_time/

A standard Oracle data file can contain up to 4,194,303 Oracle data blocks. So this also means that the maximum size of a single data file depends on the Oracle block size used. (MOS ID 112011.1) SQL> SELECT TO_CHAR (4194303 * VALUE, ‘9

Oracle's analytic Functions row_number (), rank (), Dense_rank () usage and differencesFor example, to query the payroll 7th Employee information, you can use the analysis function to do.--Query Employee information for payroll 7thSELECT *From

Merge into form: merge into [Target-table] A using [source- table sql] B ON ([conditional Expression] and [...] ...)  when matched THEN  [update sql]  when not Matched then  [ INSERT sql] Function:

Grammar:With Tempname as (select ...)Select ...– For an aliasWith TMP as (SELECT * from Tb_name)– For multiple aliasesWithTMP as (SELECT * from Tb_name),TMP2 as (SELECT * from Tb_name2),Tmp3 as (SELECT * from Tb_name3),Example: Now to get 11-14 from

CSS Startup process1) The operating system is started and calls the GI-related script in the/etc/inittab file.2) The Ohasd.bin daemon is started and the process is responsible for initiating all agent processes, including the oracssdagent_root agent

About DMP Files We use more, DMP files It is used as the file format for the Oracle Import and export tables, and today the DMP files are exported and imported for learning.DMP file ExportDMP file export is generally three kinds, they are: export