Oracle

1. Left OUTER JOIN: External Association SELECT E.last_name, e.department_id, D.department_name From Employees E Left OUTER JOIN Departments D On (e.department_id = d.department_id); Equivalent to SELECT E.last_name, e.department_id,

How do I return a table variable in Oracle's function? Too late, too much theoretical knowledge will not say, the following simply said to achieve it!.. 1, create the Table object type.To return a Table object in Oracle, you must customize a

First, control user access1, create modify user creating usersCreate/alter user new_user identified by password;Example: Create user user_1 indentified by pwd_1Alter user user_1 identified by pwd_22, give the user the right to grantGrant

Software Environment: 1. Operating system: Windows Server 2. Database: Oracle 8i R2 (8.1.7) for NT Enterprise Edition 3, Installation path: c:oracle Implementation method: 1, D:>set Nls_lang=american_america. USACII7 Or D:>set

1. The ORACLE parser processes the table names in the FROM clause in Right-to-left order, so the last table in the FROM clause (the underlying table driving tables) is processed first. In the case where multiple tables are included in the FROM

The code for the MyBatis Oracle self-increment sequence is as follows: SELECT seq_table. Nextval from dual inserts into s_id,name,age VALUES (#{s_id} #{name}, #{age}) resulttype= "int" returns an int type Keyproperty The

Indexing is the most effective way to improve data querying and is the most difficult technology to master, because proper indexing can increase efficiency by 10,000 times times, and invalid indexes may be a waste of database space, or even greatly

1. Create, configure, or delete databases by running Oracle database Configuration Assistant (You can also enter DBCA at the command line);2. Building a database using a command-line approach3. Create, configure, or delete a database by running a

Because:1) Improve performance: As far as possible the table and index of the table space stored in different on the disk, the two types of different IO data to open, so as to improve the overall performance of the disk IO; 2 Easy to manage:

Therefore, in the daily maintenance of the database, if only two times to encounter ORA-01555 errors, generally ignored, but if you often encounter this error, you need to make some adjustments to avoid the recurrence of this error. 1. Why are ORA-0

first, let's talk about what they have in common: They are essentially exclusive locks on resources that are caused by concurrency (if the database has only one session, it is not locked). Then focus on the different points: first of all , their

The role switching between Data guard master and subordinate libraries is divided into the following two kinds:1) SwitchoverSwithchover are usually artificial and planned for role swaps, such as upgrades. It is usually lossless, that is, there will

AWR's data consists of two main components:1 The system load and performance statistics stored in memory, mainly through the v$ view query;2 The Mmon process periodically saves in-memory awr data to the Sysaux tablespace in a snapshot (snapshot)

The relationship between the tables is more complex, the amount of data is much more, delete absolutely will be a big problem. So we experimented with several solutions, and now we have a summary. method One: Set cascading deletes when creating

1\ flash The table back to a point in time : Enable row movement before flash back operations SQL code ALTER TABLE EMP enable row movement; To perform a flash-back statement : SQL code Flashback table EMP to timestamp to_timestamp (' 20120

I recently made a further analysis and study of RowNum when using Oracle's rownum to implement pagination display. are summarized as follows, hope to bring you harvest.For RowNum, it is an Oracle system sequence that is assigned the number of rows

Looking at PD, double-click a table, view its preview label, and then find the CREATE statement for a table, as follows: Copy Code code as follows: CREATE TABLE Company_info ( company_id NVARCHAR2 (m) not NULL, area_id NVARCHAR2 (50),

Here is an example of how to implement the self increase of the fields in Oracle. First, create a table superamin Copy Code code as follows: CREATE TABLE Superadmin ( ID number (one) primary key, Name varchar (one) is not null

1. Create a Test table: Copy Code code as follows: DROP SEQUENCE student_sequence; CREATE SEQUENCE student_sequence START with 10000 INCREMENT by 1; DROP TABLE students;CREATE TABLE Students (ID Number (5) PRIMARY KEY,First_Name

Copy Code code as follows: --Get Early Start time Create or Replace function Fd_lastxunstart (RQ in date) return "string is" Refstr VARCHAR2 (50); V_RQ date; Begin --Get the date of the last day V_RQ: = trunc (RQ); Select Case Decode