国产av日韩一区二区三区精品,成人性爱视频在线观看,国产,欧美,日韩,一区,www.成色av久久成人,2222eeee成人天堂

Home Database Mysql Tutorial 實現(xiàn)Oracle數(shù)據(jù)庫的逐漸自增

實現(xiàn)Oracle數(shù)據(jù)庫的逐漸自增

Jun 07, 2016 pm 04:55 PM
or oracle database

1、 第一次NEXTVAL返回的是初始值;隨后的NEXTVAL會自動增加你定義的INCREMENT BY值,然后返回增加后的值。CURRVAL 總是返回當(dāng)前

將表t_uaer的字段ID設(shè)置為自增:(用序列sequence的方法來實現(xiàn))

----創(chuàng)建表
Create table t_user(
Id number(6),userid varchar2(20),loginpassword varchar2(20),isdisable number(6)
);

----創(chuàng)建序列
create sequence user_seq
increment by 1
start with 1
nomaxvalue
nominvalue
nocache

----創(chuàng)建觸發(fā)器
create or replace trigger tr_user
before insert on t_user
for each row
begin
select user_seq.nextval into :new.id from dual;
end;

----測試
insert into t_user(userid,loginpassword, isdisable)
values('ffll','liudddyujj', 0);
insert into t_user(userid,loginpassword, isdisable)
values('dddd','zhang', 0)
select * from t_user;
就可以看出結(jié)果。

linux

,
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undress AI Tool

Undress AI Tool

Undress images for free

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

MySQL vs. Oracle: Licensing, Features, and Benefits MySQL vs. Oracle: Licensing, Features, and Benefits May 08, 2025 am 12:05 AM

The main difference between MySQL and Oracle is licenses, features, and advantages. 1. License: MySQL provides a GPL license for free use, and Oracle adopts a proprietary license, which is expensive. 2. Function: MySQL has simple functions and is suitable for web applications and small and medium-sized enterprises. Oracle has powerful functions and is suitable for large-scale data and complex businesses. 3. Advantages: MySQL is open source free, suitable for startups, and Oracle is reliable in performance, suitable for large enterprises.

Redis: A Comparison to Traditional Database Servers Redis: A Comparison to Traditional Database Servers May 07, 2025 am 12:09 AM

Redis is superior to traditional databases in high concurrency and low latency scenarios, but is not suitable for complex queries and transaction processing. 1.Redis uses memory storage, fast read and write speed, suitable for high concurrency and low latency requirements. 2. Traditional databases are based on disk, support complex queries and transaction processing, and have strong data consistency and persistence. 3. Redis is suitable as a supplement or substitute for traditional databases, but it needs to be selected according to specific business needs.

How to learn Java without taking detours. Share methods and techniques for efficiently learning Java How to learn Java without taking detours. Share methods and techniques for efficiently learning Java May 20, 2025 pm 08:24 PM

The key to learning Java without taking detours is: 1. Understand core concepts and grammar; 2. Practice more; 3. Understand memory management and garbage collection; 4. Join online communities; 5. Read other people’s code; 6. Understand common libraries and frameworks; 7. Learn to deal with common mistakes; 8. Make a learning plan and proceed step by step. These methods can help you master Java programming efficiently.

MongoDB vs. Oracle: Exploring NoSQL and Relational Approaches MongoDB vs. Oracle: Exploring NoSQL and Relational Approaches May 07, 2025 am 12:02 AM

In different application scenarios, choosing MongoDB or Oracle depends on specific needs: 1) If you need to process a large amount of unstructured data and do not have high requirements for data consistency, choose MongoDB; 2) If you need strict data consistency and complex queries, choose Oracle.

Learning SQL: Understanding the Challenges and Rewards Learning SQL: Understanding the Challenges and Rewards May 11, 2025 am 12:16 AM

Learning SQL requires mastering basic knowledge, core queries, complex JOIN operations and performance optimization. 1. Understand basic concepts such as tables, rows, and columns and different SQL dialects. 2. Proficient in using SELECT statements for querying. 3. Master the JOIN operation to obtain data from multiple tables. 4. Optimize query performance, avoid common errors, and use index and EXPLAIN commands.

Oracle Software: Maximizing Efficiency and Performance Oracle Software: Maximizing Efficiency and Performance May 06, 2025 am 12:07 AM

Oracle software can improve performance in a variety of ways. 1) Optimize SQL queries and reduce data transmission; 2) Appropriately manage indexes to balance query speed and maintenance costs; 3) Reasonably configure memory, optimize SGA and PGA; 4) Reduce I/O operations and use appropriate storage devices.

What to learn Java? A summary of Java learning routes and essential knowledge points What to learn Java? A summary of Java learning routes and essential knowledge points May 20, 2025 pm 08:15 PM

Learning Java requires learning basic syntax, object-oriented programming, collection frameworks, exception handling, multithreading, I/O streaming, JDBC, network programming, and advanced features such as reflection and annotation. 1. The basic syntax includes variables, data types, operators and control flow statements. 2. Object-oriented programming covers classes, objects, inheritance, polymorphism, encapsulation and abstraction. 3. The collection framework involves ArrayList, LinkedList, HashSet, and HashMap. 4. Exception handling ensures program robustness through try-catch block. 5. Multithreaded programming requires understanding of thread life cycle and synchronization. 6. I/O streams are used for data reading, writing and file operations. 7. JDBC is used to interact with databases. 8. Network programming passes S

Connection and data visualization of Oracle databases with BI tools such as Tableau Connection and data visualization of Oracle databases with BI tools such as Tableau May 19, 2025 pm 06:27 PM

To connect Oracle database to Tableau for data visualization, you need to follow the following steps: 1. Configure Oracle database connection in Tableau, use ODBC or JDBC drivers; 2. Explore data and create visualizations, such as bar charts, etc.; 3. Optimize SQL queries and indexes to improve performance; 4. Use Oracle's complex data types and functions to implement through custom SQL queries; 5. Create materialized views to improve query speed; 6. Use Tableau's interactive functions such as dashboard for in-depth analysis.

See all articles