Oracle

Oracle Database PL/SQL package 6) package www.2cto.com 1. basic concept package (Package) is used to organize logical PL/SQL blocks or elements (variables, constants, custom data types, exceptions, processes, functions, and cursors, the package is

Oracle notes: Tables and fields (2) 2. delete a FIELD in the TABLE: www.2cto.com delete a FIELD: alter table mtable drop column (FIELD) cascade constrains; OR: alter table mytable set unused (FIELD) cascade constrains; Delete multiple fields: alter

The rownum trap in oracle is currently being optimized for an oracle SQL statement: it involves paging. For example, to query top 5 data, we need to write: www.2cto.com select * from (select * from customer order by custcredit) where rownum 2 means

Solve useradd: warning: the home directory already... when oracle11g is installed in RHEL 5 or CentOS5, www.2cto.com groupadd oinstall groupadd dba mkdir-p/u01/oracle (/u01/oracle will install Oracle 11g here) to create a user: useradd-g oinstall-G

ORA-01843 and NLS_DATE_FORMAT Problem Analysis in Oracle SQL where clause input character type parameter '19-November-08 ', so that you can directly compare with the date type, or convert the same date type comparison. Www.2cto.com if the input

Sorting background of NUll values in Oracle sorting: processing of NULL values in Oracle sorting, which is a special value type in Oracle official documentation, by default, it is regarded as the maximum value during sorting. That is to say, when a

Database flash back related statement 1 \ roll back the table to a certain time point: enable the row movement function before the flash back operation of www.2cto.com SQL code alter table emp enable row movement; execute the flash back statement:

Overview of the composition of Oracle clusterware (I) the relationship between clusterware and RAC www.2cto.com in a narrow sense, RAC refers to a "Multi-instance, single database" Environment built with "some cluster components". Here the cluster

Oracle learning 2 (data type and Table query) oracle Data Type: www.2cto.com character type: the maximum char size is 2000 characters, and the space defined by char will be occupied no matter how much content, char queries are very efficient and

Oracle temporary table application problems some people have provided the best optimization ideas on the Internet: 1. first, extract the records that meet the conditions in the large table to generate a temporary table. 2. then, associate the small

The Oracle dual Listener Configuration is based on Oracle Net. The database server may also be a client because of tnsnames. ora can have a server description, that is, only the listener will always be a server instance: Listener = n: m www.2cto.com

In Oracle, The from subquery instance applies the Oracle table complex query ---------------------------------------------------- subquery example in the word query www.2cto.com from: how to display the employee information higher than the average

Oracle Table Analysis in my opinion, the database table is analyzed to obtain the statistical information of the table, so that the database selects the correct execution path when performing Table query and other operations, so when do we need to

Oracle uses months_between (ddd. s_date, S. VALID_BEGIN_DATE) to calculate the difference of the month. The result is a decimal value. Www.2cto.com SQL code SELECT P. PILOT_ID basicInfoId, P. CLERK_CODE clerkCode, P. PILOT_NAME pilotName, S.

Using shared storage to build oracle dual-host LoadPreparation environment: two servers and one storageWww.2cto.comShows the basic principles:Www.2cto.comEnvironment:Shared storage: 172.16.0.5DB1:Eth0: 192.168.1.1Eth1: 172.160.1Vip:

Oralce writes a paging stored procedure with a returned value stored procedure (list result set) Case: Write a procedure, enter the Department number, and return information of all employees of the Department. The analysis of this question is as

SQLPLUS automatically saves the executed SQL. When learning oracle, it wants to record the executed commands and results. However, it is not a way to use SQLPLUS to save each time. It is quite troublesome to manually execute the spool, so I made a

Oracle reset initialization parameter SQL> select * from v $ version where rownum ! Uname-a Linux rac1 2.6.32-200.13.1.el5uek #1 SMP Wed Jul 27 21:02:33 EDT 2011 x86_64 x86_64 x86_64 GNU/Linux www.2cto.com 1, resetSQL> select name, value,

PL/SQL daily question: Exception Handling -- WHEN clause question: www.2cto.com catch a divisor error ("ORA-01476: divisor is equal to zero ") in this case, all the other exceptions of "Bad division" must be transmitted to the calling block intact.

SQL not in: in SQL queries, select * from t1 where c not in (select c2 from t2) If c2 in t2 has null, the result of this statement may be, only when the NULL value must be filtered out in the subquery can www.2cto.com select * from t1 where c not in