Oracle

Generally, if you installOracleServerSoftwareOracle ODBC source is automatically added, so you do not need to do anything. Now I will explain how to add Oracle ODBC source through the Oracle client. Step 1, click this link

How to use ORACLE sequence: An Oracle sequence is a database item that can generate an integer sequence. It is usually used to fill in a numeric primary key column. 1. Create sequence: Create sequence sequence_name [Start with start_num]

  Example: (1) query data in the users table. Select U. ID, U. realname, U. Sex from users U; The query result is as follows: Id realname sex1 10082 pine xx2 10084 Lin XX 13 10087 West xx4 10100 Hu xx5 10102 dragon XX 1......

Case: The salesperson's salary in the Scott. EMP table can only increase, but cannot decrease Code: Create or replace trigger tr_emp_updBeforeUpdate of SalOn EMPFor each row -- Triggered only when the salesperson is updated When (Old.

InProgramWhen defining variables, constants, and parameters, you must specify the PL/SQL data type for them. When compiling PL/SQL programs, you can use the scalar type, composite type, reference type, and lob (largeObject. The most common

The system automatically renames a table deleted from Oracle as the name starting with Bin $.You can run the show recyclebin command to view the details of the deleted table or query the table:Select * From recyclebin;Command for table

Recently, winform was used as a small tool to connect to the Oracle database. There was no problem during development and it was able to connect to the database normally. Later, it was found that the database could not be connected, and the

In large-scale project development, common databases are Oracle databases. However, an Oracle client requires a large disk. After installation, two functions are basically used: TNS Configuration Service name and sqlplus. During development, toad

The management of database files in sqlserver is relatively simple. The main concepts include: 1. File Group. Storage Allocation unit of database objects. The purpose is to accommodate more database files and expand space. 2. File. File Group

Variable declaration: Oracle variables must be declared in the declare section -- meaning that the begin end block must be created, and the block structure also forces the variables to be declared first and then used, that is to say, Oracle

Updating .....   Programming Interface OCI: the lowest, most basic, most efficient, and most complex C ++ programming interface of oracle. Basic Level: 1 (a larger number indicates a higher level, which is usually simpler and more inefficient)

Dbid is the unique representation of the ownership of the Oracle database file component. It is the ID of various ORACLE data files. Oracle creates a database with a random 10-digit string, similar to "1977880105". It can use the applications

How Should Oracle control files be understood? In my opinion, the control file records a state of the Oracle database. Like the Windows System Restoration function, it recordsValid, transaction, and specific status. It is also a database, which

I. Overview: Exp and IMP tools are logical Import and Export tools provided by Oracle all the time --- original!   Ii. Basic usage Exp user/password @ TNS [full | Owner | tables | tablespaces | transport_tablespace] file = rows = IMP

Basic concepts: 1. Protection Mode: maximum protection, maximum performance, and maximum availability. The default value is the maximum performance. 2. physical and logical backup machines: 3. Online, archived, and standby redo logs 4. Log

Introduction: The dbms_backup_restore package is really powerful. The stored procedure related to dbid setting is as follows: Procedure nidbegin (newdbname in varchar2,Olddbname in varchar2,Newdbid in number,Olddbid in number,Dorevert in

It can be understood that using RMAN to create a duplicate database is essentially the same as using dbca to create a database. The expression is different. To succeed, the key conditions are as follows: 1. RMAN is a pseudo-server tool: it can

Scenarios and requirements: Table A is a fact table, and table B is a historical table. Create Table A (fact_id int not null primary key, name varchar2 (50 )); Create Table B (log_id int not null primary key, name varchar2 (50), addtime

Oracle --> MySQL To_char (sysdate, 'yyyy-mm-dd') --> date_format (sysdate (), '% Y-% m-% D ');To_date (sysdate, 'yyyy-mm-dd') --> str_to_date (sysdate (), '% Y-% m-% D '); 1. Oracle (1) Use the to_char function to process numbers To_char

Guide] Dual is a virtual table used to form the select syntax rule. Oracle ensures that there will always be only one record in dual. We can use it to do many things. Dual is a virtual table used to form