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My SQL tuning column: https://blog.csdn.net/u014427391/article/category/8679315 For local, such as a page list sql, we can use Oracle's execution plan for SQL tuning, but for the whole system, you can know which SQLs are time consuming?Of course, you can get it by checking Oracle's shared pool, but Oracle system itself provides sev ...

Hierarchical Query Pseudo Columns Sequence pseudorandomSequence pseudocolumns cannot be used in the following constructions: VERSION QUERY pseudocolumn COLUMN_VALUE pseudocolumn OBJECT_ID pseudocolumn OBJECT_VALUE pseudocolumn ORA_ROWSCN pseudocolumn ROWID pseudo column ROWNUM pseudo column XMLDATA pseudocolumns Hierarchi ...

Introduction to MySQL 1. Basic concepts of database Database: DataBase is abbreviated as DB Role: Warehouse for permanent storage and management of data 2. Common databases A.MySQL Simple Free Database B.Oracle Large Charge Database C. SQL Server Microsoft C and. Net D.SQLite Embedded Database Andro ...

BACKGROUND: Recently, in the development of projects, the adjustment of basic indicators is involved. Relevant composite indicators and downstream dependent indicator codes all need to be replayed. unpivot row and column transitions Case: Now there is a fruit table, which records the sales volume of four quarters. Now it is n ...

ORACLE Paging Query Change from: ORACLE Paging Query SQL Syntax - The Most Efficient Paging Writing without ORDER BY sort. (Highest efficiency) After testing, this method has the lowest cost, only one layer nested, and the fastest speed! Even if the amount of data queried is large, it is almost unaffected, and the speed is ...

Originality: We sometimes encounter this kind of requirement when we are working on a project. hobby with name Zhang San needs to be merged as follows: Of course, you can also merge hobby into one column through mysql's group_comcat. That's very simple. I won't introduce it here. Build tables first, insert data SET NAMES utf8 ...

This section describes the basic contents of PL SQL The sample data listed in this section comes from the emp and dept tables under oracle user scott, as follows: 1. Introduction to plsql: 1. Concept: procedural language, procedural SQL language, is a process-oriented language. On the basis of ordinary sql, the features of programming language ...

Summary of redis use (1) (redis client use) NoSQLNoSQLFrom Baidu Encyclopedia NoSQL, refers generally to non-relational databases.With the rise of Internet web2.0 websites, traditional relational databases have been unable to cope with web2.0 websites, especially Web 2.0 pure dynamic websites of super-large-scale and highly concurrent SNS type, ...

[TOC] I. Pattern Definition The template method pattern defines some skeleton methods in an abstract class, and then defers some methods to the inherited class through the method of class inheritance. Template method pattern is a kind of behavioral pattern, and it is a common method. It does not belong to the object behavioral patt ...

Article directory 1 Preparations 1.1 Delete Oracle software before installation 1.2 Create directories 1.3 Connect SFTP tabs in CRT 2 See information about this guide 3 Check Hardware Requirements 3.1 Memory Requirements 3.2 System Architecture 3.3 Disk space required 4. Check software requirements 4.1 Operating System R ...