Database Administrator

Use mybatis-paginator to implement Paging   1. Introduction to mybatis-paginator Mybatis-paginator is an open-source project on gethub. It is used to obtain paging data in the java background. This open-source project also provides a list component (

Part 1 Database SQL language Database script comments   1. Overview Annotations play an important role in programming languages. Beautiful and proper comments not only help developers understand programs, but also improve programming efficiency (and

When I was using the database today, I suddenly found that SQL Server08 could not be connected. Problem: So I searched for this problem on the Internet and found many similar questions. Since this problem was not encountered by a few people, it

The syntax of Merge is as follows: MERGE [hint] INTO [schema .] table [t_alias] USING [schema .] { table | view | subquery } [t_alias] ON ( condition ) WHEN MATCHED THEN merge_update_clause WHEN NOT MATCHED THEN merge_insert_clause;What is MERGE

Unconditional insert Insert all in Oracle refers to inserting the same batch of data into different tables. If there is a need to insert the data in table t into t1 and t2 separately, if you do not know insert all, you may insert data twice using

Those who frequently write SQL statements should know that the main usage of Group by statements is to classify and summarize them. The following is the most common usage of Group by statements (statistics of performance by department and position ):

The previous blog introduced how to use the Navicat tool to back up Oracle. This blog introduced how to use the PL/SQL Developer tool to import and export Oracle databases. PL/SQL Developer is one of the main tools used by Oracle databases to import

Query all data table content Mysql> show tables; # view all tables in the current database + ---------------------- + | tables | + -------------------- + | biao | ceshi_biao | + -------------------- + 2 rows in set (0.00 sec) mysql> select * from

Zookeeper Where \ what? Root Pdb Remarks Control files and redo log files Y   Belongs to the CDB and not to a specific iner Shared UNDO and default database temporary tablespace Y    

Ubuntu14.04 has been out for a while. I just upgraded it to this version a few days ago and I got a fresh one. However, there was a small problem during mysql installation. record it for later use. Prerequisites: There are many ways to install mysql

Select p. id comperitorId, p. compcorp competitorName, sum (case when c. kindname = 'atm 'then c. num else 0 end) atm, sum (case when c. kindname = 'crs 'then c. num else 0 end) crs, sum (case when c. kindname = 'vtm 'then c. num else 0 end) vtm,

If there are too many fields in the table and some fields in the table are relatively large, even if you only query a limited number of fields, due to the large number of data blocks scanned during table Association and full table scan, performance

Learn database knowledge, write a blog, and sort out and consolidate knowledge. Let's take an example of what a database is. It may not be accurate enough to understand the general meaning. To learn deeply, you should read a book. Let's talk about

I. Overview: 1. The pipeline function is a function that can return a row set (nested table or array varray can be used). We can query it like a physical table orAssign a value to the set variable.2. Pipeline functions are executed in parallel. If

When creating an index, we add parallel indexes to build the index quickly. After adding parallel indexes, this column will be in parallel. When accessing an index with a degree of parallelism, CBO may consider parallel execution, which may cause

# Include Int main (){Int I;Int B [5] = {1, 3, 5, 7, 9 };Int (* a) [5] = & B;Int * m = a; // the space in the range of a is determined by the int size.For (I = 0; I {Printf ("% d \ n", m [I]);}Return 0; } The output result is 1 2 3 4 5. Here, int (*

Select CONVERT (varchar, getdate (), 120)11:06:08Select replace (CONVERT (varchar, getdate (), 120 ),\'-\',\'\'),\'\', \'\'),\':\',\'\')20040912110608Select CONVERT (varchar (12), getdate (), 111)2004/09/12Select CONVERT (varchar (12), getdate (), 11

Analysis of association Design   [Paradigm] Ideally, any table in the database will correspond to an object in real life. For example, a player is an object, a team is an object, and a competition is an object, the competition result is an object,

Zookeeper Stored procedures are compiled and permanently stored in a set of SQL statements. By creating and using stored procedures, you can improve the reusability and scalability of programs and provide modular functions for programs, it also

Conclusion 1: Official definition of memcache Free & open source, high-performance, distributed memory object caching system, generic in nature, but intended for use in speeding up dynamic web applications by alleviating database load. Official