android simulator ADT links to local database Mysql

android simulator ADT links to local database Mysql 1. Create a new link database thread and insert data into the database to view the link effectNote that if you only test the link ip between the simulator and the local database MySQl, you can directly fill in 10.0.2.2ip can be directly filled in 10.0.2.2ip can be directly f ...

Posted on Mon, 18 Nov 2019 12:45:48 -0500 by davitz38

[pure technology post]. NETStandard FreeSql v0.0.9 function Preview

New year is coming, the technical content of the home page is really less and less. I understand that you are looking forward to a holiday for the new year, my friend, I would like to pay you a visit to the early years. Brother, I got nervous from the end of November and started the development tour of ORM functional library. It took two mont ...

Posted on Mon, 18 Nov 2019 03:58:16 -0500 by mash

Annotation of MyBatis Plus to realize dynamic SQL

With MyBatis, all Dao layer methods inherit the base class basemapper < T > I. use < script > < script > script package The first way: use < script > < script > to wrap, and implement dynamic SQL like writing SQL statements in xml 1. Use the < if > < if > tag to realize fuzzy keyword sear ...

Posted on Mon, 18 Nov 2019 02:53:56 -0500 by horseygirl

Troubleshooting of MySQL nested query "LIMIT & IN/ALL/ANY/SOME"

This version of MySQL doesn't yet support 'LIMIT & IN/ALL/ANY/SOME subquery' Error message: This version of MySQL doesn't yet support 'LIMIT & IN/ALL/ANY/SOME subquery' Recently, there is such a requirement in the development process. To get the scores of the top 50 students in all subjects, first think of in (...). The ...

Posted on Sun, 17 Nov 2019 15:12:57 -0500 by dmonares

There are 8 SQL misuses that are often ignored. Have you ever stepped on a pit?

1. LIMIT statement Paging query is one of the most commonly used scenarios, but it is also the most prone to problems. For example, for the following simple statements, the general way DBA s think of is to add a composite index to the fields of type, name, create "time. In this way, conditional sorting can effectively utilize index and i ...

Posted on Sun, 17 Nov 2019 14:14:06 -0500 by cornelombaard

PHP exports large amount of data (csv)

If you want to export a large number of data at one time, such as hundreds of thousands or millions of data, there are often two problems: 1. Script execution timeout 2. Insufficient PHP memory The first problem is well solved: set ﹣ time ﹣ limit (0); when set to 0, the time of the script is not limited. However, it is not ...

Posted on Sun, 17 Nov 2019 10:34:40 -0500 by n_wattam

Process analysis of Sql execution by 02-MyBatis

Catalog Get Mapper A brief summary Important Classes Reference resources This blog focuses on MyBatis's Sql execution process. Details about caching and dynamic SQl generation during execution are not reflected in this blog. Write a blog analysis separately after the corresponding content. ...

Posted on Sun, 17 Nov 2019 04:47:36 -0500 by windwaker

Full backup and restore of mysql database using mysql dump

1 > start database binary log Check whether SQL log bin is enabled MariaDB [(none)]> show variables like 'sql_log_bin'; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | sql_log_bin | ON | +---------------+-------+ 1 row in set (0.00 sec) Use set SQL log bin = on; turn on binary log Modify profileSpecif ...

Posted on Sat, 16 Nov 2019 17:17:58 -0500 by creatives

Easy database operations with Groovy and Gradle

Groovy: Stylish Language Not everyone thinks the Java programming language is sexy.However, from the most conservative to the most bizarre start-ups, Java virtual machines are the dominant force everywhere.Today, there are many alternative languages that can be compiled as Java byte codes.There are multiple implementations of Python, Ruby, and ...

Posted on Sat, 16 Nov 2019 03:07:37 -0500 by jimiwa

4. Principle and use of spark--sparkSQL

[TOC] 1. Overview of spark SQL 1.1 What is spark SQL Spark SQL is a module Spark uses to process structured data. It provides a programming abstraction called DataFrame and functions as a distributed SQL query engine.Similar to what hive does. Features of 1.2 spark SQL 1. Easy to integrate: When you installed Spark, it was already integrated.N ...

Posted on Sat, 16 Nov 2019 01:24:56 -0500 by HokieTracks