oracle update

Original source http://bijian1013.iteye.com/blog/1895412 the difference between the for update and for update nowait First of all, if only select, Oracle will not add any locks, that is, Oracle to select There is no limit to the data read, although it is possible that another process is modifying the data in the tab

users cannot update the entire row. Does this mean that for update of columns is meaningless? It is estimated that many ORACLE students have not thought about this question [There are not many posts on the Internet ]. Now I will explain its functions. From the operation of a single table, the effects of the above two statements are indeed the same. However, when

Basic Update Statements The Oracle UPDATE statement processes one or more rows in a table and sets one or more columns to the values of you specify. Update All records UPDATE SET CREATE TABLE Test ASSELECT object_name, Object_t

From: http://blog.163.com/gaofx_hk/blog/static/193999289201172893813254/ Oracle does not have the update from syntax. There are two implementation methods:1. subquery:UpdateSet field 1 = (select field expression from B where ...),Field 2 = (select field expression from B where ...)Where logical expression Update multiple fields: Statement 1:

by other transactions, the current lock transaction with the conflict, plus nowait, the current transaction will end will prompt the error and immediately end the statement and no longer wait). 2. The wait clause specifies the number of seconds to wait for another user to release the lock, preventing an indefinite wait. The advantages of the use for UPDATE WAIT clause are as follows:1. Prevent indefinitely waiting for a locked line;2. Allow more cont

Original address: http://www.cnblogs.com/quanweiru/archive/2012/11/09/2762223.html1 . The difference between for update and for update nowait: First of all, if only Select,Oracle will not add any lock, that is, Oracle to Select read the data there is no limit, although it is possible that another process is modifying t

The syntax for implementing update Association update in SQL Server and Oracle is different. You can use inline view (embedded view)In general, sqlserver is simpler. The test example is as follows: Create Table tmp_a(Cpcode varchar2 (10 ),Sb_ym varchar2 (6 ),Flag char (1)); Create Table tmp_ B(Cpcode varchar2 (10 ),Sb_ym varchar2 (6 ),Flag char (1)); Insert into

expensive thanMergeWay slightly higher. ALTER TABLE TEST2 add constraint Pk_test2 primary key (ID); --/*+ BYPASS_UJVC */ Update (select/*+ bypass_ujvc */a.id aid,a.name aname,b.id bid,b.name bname from test1 a,test2 b where a.id=b.id) t Set aname = Nvl2 (aname,bname,aname); Use parallelism to speed up large volumes of data updates: Merge/*+parallel (test1,4) */into Test1 using Test2 On (test1.id = test2.id) When matched then

In general, we only update a single record, but there are few batch updates. Currently, we provide three methods for batch update: 1. Batch update Update test a set a. dept_no = (select B. dept_no from test1 B where a. emp_no = B. emp_no) 2. Batch update with multiple col

Direct query.SELECT * from A1 t;The data taken at this time is the pre-run data, and other users do not get the data modification at the same time.Real-time update queriesSELECT * FROM A1 t for update;For update updates, other managers can do the data operation with update, which limits the number of users, fewer conne

Table join update statement: Scenario: Table: Am_approve_list_log_sammy Am_approve_list_sammy Update field: Emp_id, approver_sequence, approver_id Join field: Emp_id, approver_id Method 1: Update Am_approve_list_log_sammy Set (A. emp_id, A. approver_sequence, A. approver_id) = ( Select B. emp_id, B. approver_sequence, B. approver_id From

Implementation statement for Oracle Update Data Update Sql>--Create demo table Sql> CREATE TABLE Employee ( 2 ID VARCHAR2 (4 BYTE) not NULL, 3 first_name VARCHAR2 (BYTE), 4 last_name VARCHAR2 (BYTE), 5 start_date Date, 6 end_date Date, 7 Salary Number (8,2), 8 City VARCHAR2 (BYTE), 9 Description VARCHAR2 (MB) 10) 11/ Table created. Sql> Sql>--Prepa

Tags: style blog color sp data on div log1.update dataUPDATESET= (selectfromwhere t.xh= b.vlbi_ XH)wherelike'14%';2. Judging men and women according to their ID numbers Decode (mod (To_number (substr ( ID number ', 17, 1) ", Span style= "color: #800000; Font-weight:bold; " >2), 0, 2 "" 1 ") A. Intercept the second-to-last digit of the ID first B. is divisible by 2 C. If the remainder is 0, Then 2-female D. If the remainder is not 0, then 1-male

Implementation statement for Oracle Update Data Update Sql>--Create demo tableSql> CREATE TABLE Employee (2 ID VARCHAR2 (4 BYTE) not NULL,3 first_name VARCHAR2 (BYTE),4 last_name VARCHAR2 (BYTE),5 start_date Date,6 end_date Date,7 Salary Number (8,2),8 City VARCHAR2 (BYTE),9 Description VARCHAR2 (MB)10)11/ Table created. Sql>Sql>--Prepare datasql> INSERT INTO

Cp_index_statistics_rec Set is_validate = 1, stat_data = Indexdata, Stat_create_date = (select Sysdate from dual) where stat_date = To_date (To_char (statdate, ' yyyy/mm/dd '), ' yyyy/mm/dd ') and cp_id = cpid and Index_type_code = Indextypecode and Index_item_code = Indexitemcode; Commit End End If; return numb;end Fn_merge_index;Note that the To_date (To_char (statdate, ' yyyy/mm/dd '), ' Yyyy/mm/dd ') is written in To_date (Statdate, ' yyyy/mm/dd '), which, depending on the