Oracle

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

I. Using profile to manage user passwordsOverview: Profile is a collection of commands that are password-constrained and resource-constrained, and when a database is established, Oracle automatically establishes a profile called default. When the

VBA Connection Oracle needs to add references:After that, the connection string is: Provider = msdaora.1; password=******; User Id=xxxxxxx;data source=dbid; Persist Security Info=trueThen use the standard package of ADO, 1, use ado.connection, open

1. Use arithmetic expressions to perform operations on the data during queryThe student table structure is as follows:The last salary represents each person's monthly salary, I now want to inquire each person's annual salary:2. Use the NVL function

Grouping functionsIn a grouping function, if there is a find item grouped, the other items must also be grouped, for example, the following statement will be an error because Sal is grouped, and ename is not grouped:1. Show the highest paid

As we all know, there is a snapshot in the VMware virtual machine function, we can put the system at this time to save the state, the side of a contingency event, or restore the system, Oracle also has similar features.First create a student

DeclareV_exists_table Number;begin Select Count(*) intoV_exists_table fromAll_tableswheretable_name= 'NUMBERS'; ifV_exists_table<> 0 Then ExecuteImmediate'drop table NUMBERS'; End if;End;/Create TableNumbers (ID Number

Oracle optimizes or replaces several words in, exists, and union. Test No problem!Select the appropriate statement according to the actual situation. Assume exponential, or full table scan, in and not in should be used with caution. Doing so will

Feature Description:The first is to do a no-field aggregation, and then to aggregate each field in turnTo create a table: View CodeInsert test data: View CodeROLLUP:Select t.classid,t.studentname,SumfromGroup byQuery Result:Cube:Select

Original: Novice Oracle installation and use Getting StartedA Installing OracleStep1 Download the Oracle compressed package and unzip it to the same folderSTEP2 Double-click setup.exe to installSTEP3: Enter the following interface configuration:Do

Oracle Custom Exceptions ~ ~DECLAREv_ename emp.ename%TYPE;BEGINSELECTename into V_ename fromEMPWHEREsal = &v_sal;Dbms_output.put_line (' Employee Name: '| | | v_ename);EXCEPTION whenNo_data_found ThenDbms_output.put_line (' There is no wage for '| |

A Installing OracleStep1 Download the Oracle compressed package and unzip it to the same folderSTEP2 Double-click setup.exe to installSTEP3: Enter the following interface configuration:Do not fill in the mailbox, remove the updateIn addition to

If there are now three nodes in the RAC cluster C1, C2, C3:If you want to uninstall the C3 node.1. Delete the C3 instance on C1 or C2Run DBCAThen select Oracle Real application Clusters DatabaseSelect Instance ManagementSelect Delete an

Oracle mail, permission issues, oracle mail permission -- CreateACL BEGIN DBMS_NETWORK_ACL_ADMIN.CREATE_ACL (acl => 'email _ server_permissions.xml ', Description => 'enables network permissions for the e-mail Server ', Principal => 'ljz ', Is_grant

How do Oracle beginners know common data tables such as EMP, DEPT, and SALGRADE? Graphic operation Oracle Database beginners often mention several common database tables in some books, such as EMP, DEPT, and SALGRADE. Where are these tables

ORACLE user name change Oracle user passwords have been frequently modified before, but few user names have been modified. In the past, only one user 1 can be created, user 2 data can be imported to user 1, and deleted by user 1. This is very

Oracle SQL optimization 1The data size of the two schemas is almost the same as that of the development. However, for the same SQL statement, schema a runs for 6 minutes and Schema B only comes out in 5 seconds. The SQL statement is as

Add an oracle Import/Export File In the past two days, oracle has imported and exported table data. 1. oracle provides three ways to Import and export files. (1) Oracle export/import (2) slq export/Import (3) PL/SQL export and import The second

Oracle SQL optimization 2After receiving an SQL statement submitted by the developer, it is slow in high concurrency and can be optimized:This SQL statement is used to perform Left join on another table. First, let's take a look,SQL> select l. vcno,

Scenarios and solutions for failure of ora-01653 tablespace Expansion Process of generating ora-01653 tablespace expansion failure: DBF is placed on the E disk and the E disk has only 200 M remaining. -- 1. Create a tableDrop table bigtab; Create