Oracle

Source: https://www.cnblogs.com/linjiqin/archive/2012/01/15/2323030.htmlFirst, what is the waterline (high water Mark)?All Oracle segments (segments, where, for ease of understanding, suggest segment as a synonym for a table) have a limit on the

1.rownum is a pseudo-column, which is added after getting the query result set (gets a record plus a rownum). Adds a 1-based serial number to the qualifying result.egSelect from Ur_user_info where rownum AttentionRowNum is dynamic, it must have

One, date format conversion　　To_char (date, ' format ');　　Select To_date (' 2005-01-01 ', ' yyyy-mm-dd ') from Dual;select to_char (sysdate, ' Yyyy-mm-dd HH24:mi:ss ') from dual;　　Second, the number format conversionTo_char (number, ' format

What the sequence is, the popular point is that the sequence is arranged in a certain order, the sequence will automatically increment you, generate a unique serial number;Oracle database is different from SQL Server database, there is no

--Create a test tableCreate or Replace TableStudent (XH Number(4),--School NumberXmvarchar2(Ten),--nameSexChar(2),--SexBirthday date,--DateSal Number(7,2)--Scholarships);--Add a fieldAlter TableStudentAdd(StudentID Number(Ten));--Add multiple

First, write the scriptvim/home/backup/oraclebk.sh#! /usr/bin# path name, specifying the path of the backup filepath=/home/backup/oracledata# the backup database filename filename= ' date + '%y%m%d_%h%m ' #切换至指定路径 according to the specified date

All knowledge is better than DEMO,SOThe test table required by the demo CREATE TABLE" SCOTT". " TEST "(" ID " Number(6,0) not NULLENABLE, "USERNAME"VARCHAR2( -BYTE), "Userpwd"VARCHAR2( -BYTE), "New_email"VARCHAR2( -BYTE), "RegDate" DATEDEFAULT NULL,

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 '),

1. View all table space size, Remaining amount:Select Dbf.tablespace_name,Dbf.totalspace "Total (M)",Dbf.totalblocks as total block number,Dfs.freespace "Total remaining (M)",Dfs.freeblocks "Number of remaining blocks",(dfs.freespace/dbf.totalspace)

prompt Create a function F_getprocnameCREATE ORREPLACEFUNCTION f_getprocname RETURN VARCHAR2-- gets the name and caller of the function or stored procedure itself isL_ownerVARCHAR2( 30);L_nameVARCHAR2( 30);L_linenonumber; L_typeVARCHAR2( 30);

StaticOracleConnection mqracleconnecting =NULL; Public Staticoracleconnection qracleconnecting {Get { Try { if(Mqracleconnecting = =NULL) mqracleconnecting=NewOracleConnection (JKSG);

Grammar:Create or Replace as SELECT * from QueryTable[s]Instance:Create or Replace ViewVm_wo asSelect '2' asSources,wo_nbr,wo_lot,wo_cust,wo_part,wo_rel_date,wo_due_date,wo_qty_ord,wo_status,wo_line,wo_so_nbr,wo_so

Import ExportExport a table from a remote databaseexp newsoft/[email protected]:1521/taizhouyuant file=d:\\database\\user_table.dmp tables=user_table Importing a DMP file into a local libraryimp system/[email protected]

Solve the query error caused by data duplication and the data duplication query error. In development, query errors are often reported due to multiple data entries. The following method solves this problem with one click. 1. query the number of

How to modify the field order in an Oracle database table Preface Some time ago, someone asked me a question about the order adjustment of table fields in Oracle. The problem is that after the table structure is designed, if you need to add a field

Explain the usage of common Oracle functions Trunc and Trunc, oracletrunc 1. Trunc (date) Trunc intercepts data of the date type with the specified Element Syntax: trunc (date, [format]) Date-date format Value Format-the date format is 'mm' or 'yyyy

Solution for Oracle 12.2 listening failure, oracle12.2 In their own virtual machine experiments, suddenly found that the use of PL/SQL Developer can not connect to the database, error ORA-12514, said the listen was not started. First, introduce the

Oracle query OVER (partition by...) usage, oraclepartition All examples are created under Scott, an Oracle user. Note: The Red order by in the title indicates that order by must be included when this method is used. 1. rank ()/dense_rank () over

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: =

Solve the Oracle string Sorting Problem that contains numbers and special symbols. Problem description: A residential area needs to be sorted by the residential area, building, unit number, and room number. However, when sorted by the address