Oracle

first, the recovery of the tablefor the mistakenly deleted table, as long as not using the Purge permanent delete option, then recover from the flash back area hope is quite large. The general steps are:1. Query the deleted table from Flash

First, the indexThe data in the table is unordered, so it is called the heap table, which means that the data is stored randomly. Because the data is stored randomly, a full table scan is required when querying. The index is the order of the

Asked a question yesterday by a colleague, the question is the if logic block in the Oracle stored procedureTell him about it:Create or Replace procedureTestifelsif (Numb Number) is 　　 begin 　　　　 ifNumb= 1 ThenDbms_output.put_line (1); Else ifNumb=

Oracle take month-without the previous 0Today, just take the month and the number of days, if there are 0 in front of the month to remove 0. For example, 2010-01-08, the required result is 1-8. Leads to a series of SQL statementsFirst: Using

Returns a non-null value from two expressions.GrammarNVL (EExpression1, EExpression2)ParametersEExpression1, EExpression2If the eExpression1 evaluates to a null value, NVL () returns EEXPRESSION2. If the EExpression1 evaluates to a value other than

Oracle Default database userWhen a new database is created, Oracle automatically creates 3 database users for us.1.sys User: SYS user is a super User in Oracle. All data dictionaries and views in the database are stored in the SYS mode (what is the

What is a sequence?A sequence is a database object used to generate a unique, contiguous integer. A sequence is typically used to automatically generate a value for a primary key or unique key. Sequences can be in ascending order or in descending

The way to use bulk binding (bulk binding). When looping through SQL statements that execute a bound variable, a large number of context switches occur in PL/SQL and in the engines (switches). With bulk binding, data can be batched from the Plsql

Oracle deletes duplicate data with only one query and the SQL statement to delete duplicate records--1, look for redundant records in the table, duplicate records are based on a single field (ID) to determineSelect * fromTablewhereIdinch(SelectId

1. Official website;Http://www.oracle.com/technetwork/database/enterprise-edition/downloads/index.html2. Database URL: 'Http://www.oracle.com/technetwork/database/enterprise-edition/downloads/index.html650) this.width=650; "Src="

window function First_value/last_valuerowsbetween... preceding and. .. followingrangebetweeninterval CurrentRowlag (sum(Tot_sales),1), lead--① List of monthly orders and total orders for the whole year--② lists the total monthly orders and the total

(Rank, Dense_rank, Row_number) ①row_number:12345The row_number function returns a unique value that, when the same data is encountered, is incremented sequentially in the order in which the records are recorded in the recordset. ②dense_rank:12223The

1. Download the Oracle installation package (two compressed files) on the official website, and select the first page of accept License agreement2, extract two compressed packets to the current folder, will find automatically extracted into a folder

Question one:When you run Runinstaller, specify the path of compression. /stage/components/oracle.jdk/1.5.0.17.0/1/datafiles "is invalid. The decompression command failed. Please check the Oraparam.ini.Check that there are no JDK files in the

Recursive operation of Oracle (tree operation) Start with org_id = ' 1 ' Connect by prior parent_id=son_id 1. Preface    Oracle's recursive operation, in our web page directory structure will be used frequently, is said to be the interview often out

The child node is traced to the root node.SELECT * from persons.dept start with deptid=76 connect by prior Paredeptid=deptidTraverse the child nodes (without the root node) through the root node.SELECT * from persons.dept start with Paredeptid=0

first, the SQL base languageDECLARE -- Statement varchar2 (ten-- Variable or object BEGIN A:=' Xiao Ming ') ; -- : = denotes assigning a value to a variable - - output with Dbms_output.put_line () END;Second, branchDECLARE --StatementA

1, Win+r, run regedit, enter the Registry Editor.650) this.width=650; "Src=" https://s4.51cto.com/wyfs02/M02/00/05/wKiom1mU_ZTw-bDjAAAwxumrmls450.png-wh_500x0-wm_ 3-wmp_4-s_1093241014.png "title=" 20170817101937.png "alt="

Backup RecoveryConfigure RecoverabilityRedundancyControl file (mirror)Sql> Show Parameter Control_filesSql> select * from V$controlfile;To modify a path:$ cd $ORACLE _home/dbs$ CP Spfileorcl.ora Spfileorcl.ora.bakSql> alter system set control_files=

Nomount StageOracle starts the Nomount process he loads the parameter file (Spfiledid.ora Spfile.ora Initsid.ora and then allocates memory based on the parameter to open the alert file to write the log)>startup Nomount>show parameter SPFile