Oracle

Inquire1. GROUP BY2. Basic functionsAVG (product mean) AVG (column_name) for this column of the product mean valueSUM (sum) sum (column_name) The sum of this columnMax (max) max (column_name) to find the maximum value in this columnMin (min) min

Create or Replace procedure P_outputdebug (a varchar2,b varchar2,c varchar2)IsVfilename varchar2 (100);OutputFile Utl_file. File_type;BeginSelect ' Rfid_ ' | | a.rfid| | '. LogInto VfilenameFrom Tbl_animal_info a where a.rfid= ' 330100000078176

Oracle Learning Series 3************************************************************************************ Multi-table query: 1, SQL1999 syntax support for multi-table queries 2, the use of grouping statistics and statistical functions 3,

Java development process generally use LOG4J to log the program's running logs to the file, in the Oracle stored procedures also need to log, I will work in a log of my own package to share out, in fact, very simple, I hope that we have more

-This SQL statement is used to implement the Oracle background record operation log, instead of or supplementing the application's operational logs.--1. Corresponding Log Record table-------------------------------------------------------------------

First, IntroductionThis section focuses on how to manage permissions and roles in Oracle, and what the difference between permissions and roles is.When a user is just established, the user does not have any permissions and cannot perform any action.

First, IntroductionA role is a collection of commands related to permissions, and the primary purpose of using roles is to simplify the management of permissions.Assume that there are user a,b,c in order for them to have the following permissions1.

I. Naming rules for table and column names1), must start with a letter2), length cannot exceed 30 characters3), cannot use Oracle's reserved words4), can only use the following characters a-z,a-z,0-9,$, #等Ii. Types of data1), character classChar has

1. Oracle UserThere are two types of Oracle users, one is System user SYS system, the other is ordinary user;The view Dba_users stores all user information;To create a user:Create user username identified by password default Tablespace table

First, what is a businessTransactions are used to guarantee the consistency of data, which consists of a set of related DML statements that are either all successful or fail altogether in the group's DML (data manipulation language, additions and

I. Formatting dates when using To_date () in Oracle need to be aware of format codessuch as: Select To_date (' 2005-01-01 13:14:20 ', ' yyyy-mm-dd HH24:mm:ss ') from dual;The reason is that SQL is case-insensitive, mm and mm are considered the same

There is also a dual virtual table similar to Oracle in MySQL: The official statement is purely to satisfy the select ... from ... This habit problem,MySQL ignores the reference to the table.You must pay attention to the following: SELECT *

Ora-01012:not logged on exceptionCause of the problem: the application may have a bug that did not release the connection in time.Workaround: The root of the problem is to modify the processes value, or prohibit some unusual access.Problem-Solving

Code:Sqlplus/Nologconn/ asSYSDBA//Create an accountCreate UserTechrpt_data identified byTechrpt_data;//Create a temporary table spaceCreate Temporarytablespace techrpt_data_temptempfile'D:\ORACLE\ORADATA\ORCL\TECHRPT_DATA_TEMP.dbf'size

Summary: Virtual columns can be used for special occasions, essentially similar to function columns (that is, the columns already in the table are computed by the function), "The virtual columns are not stored in the database and are returned to the

After the Oracle 11g is installed, the user name and password are not remembered when logging in. Workaround: Create a new userFirst step: Log in As SystemCMD--->sqlplusPrompt for user name, then enter Sqlplus/as SYSDBA, the password is empty.

Database version: 11.2.0.4 The database plane can restrict access to IP by configuring the relevant parameters in the Oracle Sqlnet.ora file.First, modify the Sqlnet.ora fileSqlnet.ora file in the $oracle_home/network/admin directory, add the

ORACLE_11G has 32-bit and 64-bit two versions, 64-bit computers can be installed in 32-bit versions, but 32-bit computers can not be 64-bit, if you are 64-bit, it is recommended that you install a 64-bit version.Install package Download 32-bitHttp://

For a traditional relational database management system (RDBMS), such as Oracle, MySQL, etc., are stored and retrieved data in the database, in Oracle, a schema to represent a logical data structure or a collection of schema objects, schema objects

Oracle instances and Oracle databases (Oracle Architecture) -- ===================================================== === -- Oracle instance and Oracle Database (Oracle Architecture) -- ===================================================== === /* For