oracle dba fundamentals

. Import role DataA. First enter the DOS consoleB, enter the exported data directory, such as: CD C:/userdirC, Input command, IMPD, enter user name, password, import this data to the userE, followed by the return, enter key can beF, prompt to enter the user name, password, this is the data from which user to export, is that user's10. Sqlplus Common CommandsA, set Linesize 120 can set the Sqlplus display buffer size;B, set pageSize 20 to set the display size per pageC, edit the current SQL statem

Tags: style color data SP AMP c work AD managementORACLE DBA responsibility is basically equivalent to daily work.0. Database design1. Creation and management of schema Objects (table, index, etc.)2. Management of things, such as concurrency3. SQL Tuning4. User management, Rights Management5. Real-time operational monitoring (with Toad, Statspack), for SQL-related content, tuning------------------------------------------------------------------------

function, aggregate function, analytic function)6.1 Single-line function6.1.1 character functions6.1.2 Date functionSysdate-System Current dateExample: select Sysdate from dual;--->dual: Virtual table6.1.3 Numeric functions6.1.4 conversion function6.1.1.1 To_char ()Convert to String typeExample: SELECT to_char (sysdate, ' YYYY ' year "fmmm" month "FMDD" Day "HH24:MI:SS") from dual;--Output system Current date6.1.1.2 to_date ()Convert to date typeExample: SELECT to_date (' 2012-01-12 ', ' YYYY-M

link is not# Sqlnet.ora Network Configuration File:d:\app\user\product\11.2.0\dbhome_3\network\admin\sqlnet.ora# Generated by Oracle configuration tools.# This file was actually generated by NETCA. But if customers choose to# install ' Software only ', this file wont exist and without the native# Authentication, they'll is not being able to connect to the database on NT.Sqlnet. Authentication_services= (NTS)NAMES. Directory_path= (TNSNames, Ezconnect

blocking the completion of the statement and inform the owner of the transaction, if necessary, to break the transaction.Sql> Select Sql_text,saddr from V$sqlarea,v$session 2 where v$sqlarea.address=v$session.sql_address 3 and Sql_text Like ' Alter tablespace% '; Sql_text saddr----------------------------------------------------------------- -alter tablespace test_tbs01 Read Only 0000000070f6fe40-in//This is the session address where the table space is set as a read-only statement sql> select S

statistics, calculate */select count (*) from ScheMa.tablename; --Statistics out the total number of rows in the table select DISTINCT (ind_row) from Schema.tablename; --the distinct value of the column in which the index is counted--is then calculated purely by hand?/* Query waits for events */select event, sum (Decode (wait_time, 0, 1, 0)) "Current Wait", Sum (Decode (wai T_time, 0, 0, 1)) "Not currently waiting", COUNT (*) "Total" from v$session_wait GROUP by event ORDER by Count (*) desc;

ORACLE11GR2) (7) Nocycle: Indicates stop generation of next value after maximum value is reached (8) Cycle: Indicates that the loop continues to generate an ordinal from n after the maximum value has been reached (9) Conditions that must be met: n>=n4,n Three, the effect demonstration 1. Create a sequence name seq_1 the start value is 1, the maximum value is 5, and then increment the 1 nocycle,sql statement as follows: 1 CREATE with 1 by 1 5 1 ten; 　　As shown in 1-1, the sequence seq_1 is cre

secondsDate representation range: January 1, 4712 A.D.-December 31, 9999 CE②timestampAccurate to fractional seconds①blobMaximum storage size 4GB, stored in binary form②clobMaximum storage size 2GB, stored as a string· Manage tables　Basic syntax: CREATE TABLE table_name(column_name data_type, ...);Example: CREATE TABLE userinfo(ID Number (6,0) primary key,Username VARCHAR2 (20),Password VARCHAR2 (20),RegDate Date);　　① Adding fieldsSyntax: ALTER TABLE table_name ADD column_name data_type;　　　　

TABLE Table name" Column,column. "As subquery, such as: Modify Table Structure 1. Add fields ALTER TABLE name add field name data type [default defaults] 2. Modify fields (data type and default values) ALTER TABLE name modify field name data type [default value] 3. Modify the field name ALTER TABLE name rename column name to new column name 4. Delete a field ALTER TABLE table name drop column name Modify Table Name Rename old table name to new table name Delete a table DROP table Name Add no

There are two types of data type conversions for Oracle: Implicit conversions and explicit conversions. Try to use explicit conversions when you use them.Implicit conversions are typically Varchar2 or char conversions to number and date, or vice versa. Example,hir_date> ' 1-jan-2014 ' string is implicitly converted to the date type, and select ' 53.5 ' +23 from dual is implicitly converted to the number type for the string.An explicit conversion:An ex

Learning Oracle is a complex and tedious process. In the face of a vast array of Oracle official materials, new features, MOS materials and a variety of internal knowledge, we always feel overwhelmed. However, this is often the fun we keep, accumulate and pursue.In Oracle 11g, a third connection method that breaks traditional private/shared connections is present

. V.X$BH and buffer header each buffer has a record in the X$BH. There is an important field in the X$bh TCH ,TCH is the acronym for Touch, indicating the number of accesses to a buffer, the more times thebuffer is accessed, the more sought That is, there may be a problem with hot spot block competition queries the current database for the busiest buffer Select *From (select Addr,ts#,file#,dbarfil,dbablk,tchFrom x$bhOrder by tch Desc)Where rownumIn conjunction with the information in dba