总结如下: DDL是一种消耗资源非常大的操作,运行时尽量不要使用DDL语句,应用程序需要的临时表应在运行之前就开始创建。不必在每个存储过程中创建一次。临时表总是存在的,他们作为对象存在于数据字典中,并且总是保持为空,直到有会话在其中放入数据 1 创
总结如下:
DDL是一种消耗资源非常大的操作,运行时尽量不要使用DDL语句,应用程序需要的临时表应在运行之前就开始创建。不必在每个存储过程中创建一次。临时表总是存在的,他们作为对象存在于数据字典中,并且总是保持为空,直到有会话在其中放入数据
1 创建临时表
Sql代码
create global temporary table 表名
(
ID VARCHAR2(100 CHAR),
NAME VARCHAR2(100 CHAR)
)
on commit preserve rows;
2 创建存储过程
Sql代码
create or replace procedure proc_XXX(
mycur out SYS_REFCURSOR
as
TYPE My_CurType IS REF CURSOR;
CUR_1 My_CurType;
tempa varchar2;
tempb varchar2;
--此处可声明更多变更^_^
begin
OPEN CUR_1 FOR select * from 表名;
--使用前先清空
execute immediate 'truncate table 临时表表名';
LOOP
FETCH CUR_1 INTO tempa;
EXIT WHEN CUR_1%NOTFOUND;
--进行相关的业务查询,将结果返回于更多变量上,插入临时表数据
tempa:='1';
tempb:='jack';
insert into 临时表表名(ID,NAME)values(tempa,tempb);
commit;
end loop;
open mycur for select * from 临时表表名;
CLOSE CUR_1;
message :='查询临时表成功';
EXCEPTION
WHEN OTHERS THEN
message :='查询临时表失败';
end proc_XXX;
参考更多
1 创建临时表,插入数据,返回结果集
Sql代码
CREATE OR REPLACE PROCEDURE Report_Month_Responsibility(
o_cur OUT SYS_REFCURSOR
)
IS
STR VARCHAR2(200);
tb_count INT;
BEGIN
--先判断全局临时表是否存在,没存在则重新建立:
select count(*) into tb_count from dba_tables where table_name='REPROTTEST';
if tb_count=0 then
STR:=' CREATE GLOBAL TEMPORARY TABLE REPROTTEST(
ID INT,
ANAME VARCHAR2(20)
) ON COMMIT PRESERVE ROWS';
execute immediate STR;
end if;
STR:='INSERT INTO REPROTTEST(ID,ANAME) VALUES(1,''1'')';
execute immediate STR;
COMMIT;
STR:='SELECT * FROM REPROTTEST';
OPEN o_cur FOR STR; -- 给游标变量赋值
END Report_Month_Responsibility;
2 调用存储过程
Sql代码
CREATE OR REPLACE PROCEDURE proc_X()
IS
v_ID INT;
v_ANAME VARCHAR2(20);
--定义游标:
v_account_cur SYS_REFCURSOR;
BEGIN
--调用存储过程:
Report_Month_Responsibility(v_account_cur);
fetch v_account_cur into v_ID,v_ANAME;
--用循环显示游标中的记录:
while v_account_cur%found loop
dbms_output.put_line('The value of column ID is: '||v_ID);--打引列ID
dbms_output.put_line('The value of column ANAME is: '||v_ANAME);
--打引列ANAME
fetch v_account_cur into v_ID,v_ANAME;
end loop;
close v_account_cur;
execute immediate 'truncate TABLE REPROTTEST';
end proc_X;

Stored procedures are precompiled SQL statements in MySQL for improving performance and simplifying complex operations. 1. Improve performance: After the first compilation, subsequent calls do not need to be recompiled. 2. Improve security: Restrict data table access through permission control. 3. Simplify complex operations: combine multiple SQL statements to simplify application layer logic.

The working principle of MySQL query cache is to store the results of SELECT query, and when the same query is executed again, the cached results are directly returned. 1) Query cache improves database reading performance and finds cached results through hash values. 2) Simple configuration, set query_cache_type and query_cache_size in MySQL configuration file. 3) Use the SQL_NO_CACHE keyword to disable the cache of specific queries. 4) In high-frequency update environments, query cache may cause performance bottlenecks and needs to be optimized for use through monitoring and adjustment of parameters.

The reasons why MySQL is widely used in various projects include: 1. High performance and scalability, supporting multiple storage engines; 2. Easy to use and maintain, simple configuration and rich tools; 3. Rich ecosystem, attracting a large number of community and third-party tool support; 4. Cross-platform support, suitable for multiple operating systems.

The steps for upgrading MySQL database include: 1. Backup the database, 2. Stop the current MySQL service, 3. Install the new version of MySQL, 4. Start the new version of MySQL service, 5. Recover the database. Compatibility issues are required during the upgrade process, and advanced tools such as PerconaToolkit can be used for testing and optimization.

MySQL backup policies include logical backup, physical backup, incremental backup, replication-based backup, and cloud backup. 1. Logical backup uses mysqldump to export database structure and data, which is suitable for small databases and version migrations. 2. Physical backups are fast and comprehensive by copying data files, but require database consistency. 3. Incremental backup uses binary logging to record changes, which is suitable for large databases. 4. Replication-based backup reduces the impact on the production system by backing up from the server. 5. Cloud backups such as AmazonRDS provide automation solutions, but costs and control need to be considered. When selecting a policy, database size, downtime tolerance, recovery time, and recovery point goals should be considered.

MySQLclusteringenhancesdatabaserobustnessandscalabilitybydistributingdataacrossmultiplenodes.ItusestheNDBenginefordatareplicationandfaulttolerance,ensuringhighavailability.Setupinvolvesconfiguringmanagement,data,andSQLnodes,withcarefulmonitoringandpe

Optimizing database schema design in MySQL can improve performance through the following steps: 1. Index optimization: Create indexes on common query columns, balancing the overhead of query and inserting updates. 2. Table structure optimization: Reduce data redundancy through normalization or anti-normalization and improve access efficiency. 3. Data type selection: Use appropriate data types, such as INT instead of VARCHAR, to reduce storage space. 4. Partitioning and sub-table: For large data volumes, use partitioning and sub-table to disperse data to improve query and maintenance efficiency.

TooptimizeMySQLperformance,followthesesteps:1)Implementproperindexingtospeedupqueries,2)UseEXPLAINtoanalyzeandoptimizequeryperformance,3)Adjustserverconfigurationsettingslikeinnodb_buffer_pool_sizeandmax_connections,4)Usepartitioningforlargetablestoi


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

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

Hot Article

Hot Tools

ZendStudio 13.5.1 Mac
Powerful PHP integrated development environment

DVWA
Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software

mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),

SublimeText3 English version
Recommended: Win version, supports code prompts!

MantisBT
Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.
