A preliminary study of reptiles: a review of crawling for Jingdong commodities

Original pickle seven, reprint please indicate the source. Methods used: Mysql database, python language, regular expression re With the comment url obtained (url method to get JD comments) , now we can crawl the user nickname and url. As a beginner, I use the regular expression to match the url data.1, ...

Posted by projectshifter on Wed, 04 Mar 2020 22:26:33 -0800

[MySQL]: Use DDL to operate databases, tables

1. DDL Operation Database Keyword should be capitalized. For easy memory, this article is in lower case. DDL(DATA Definition Language): A data definition language used to define database objects. 1. Create a database create database db1; #Create a database named mydb create database if not exists ...

Posted by Anders_Scales on Wed, 04 Mar 2020 18:50:55 -0800

How to deal with global exception in microservice

In microservices, global exception handling is an objective problem that must be solved. If these exceptions are not handled well, some unfriendly error messages will be displayed to users, such as null pointer exceptions, SQL execution errors and other exceptions, which are certainly incomprehensible t ...

Posted by dniry on Wed, 04 Mar 2020 02:35:09 -0800

Test high pay must see: 5 steps to teach testers how to quickly solve database queries

Mysql query questions, not only has a high exit rating, but also has a great impact on salary negotiation, so it plays an important role. 1. Almost all software test questions will have Mysql query exercises. Large companies with high salaries will select more excellent testers because of the number ...

Posted by kylevisionace02 on Wed, 04 Mar 2020 01:40:49 -0800

Search with MySQL regular expression

MySQL must know must know Regular expressions are special strings (character sets) used to match text. Three tables used: customers, products, and vendors Basic character matching: the keyword REGEXP is followed by a regular expression #Retrieve all rows of column prod'u name containing text '1000' ...

Posted by tofi84 on Tue, 03 Mar 2020 23:24:17 -0800

Introduction to libdbclient interface

This is a magical development interface! It supports access to mysql, sqlite, Dream and oracle databases! It provides a unified C++ abstract interface externally, hides the internal implementation details, and has a learning cost of 0 for users! It provides abstract result table objects (result_ta ...

Posted by khovorka on Tue, 03 Mar 2020 19:51:13 -0800

Spark SQL dataframe, DataSet and RDD

Spark SQL directory DataFrame DataSet RDD DataFrame, conversion between DataSet and RDD DataFrame, relationship between DataSet and RDD The commonness and difference between DataFrame, DataSet and RDD 1.Spark SQL Spark SQL is a module used by spark to process structured data. It provides two progr ...

Posted by tracivia on Tue, 03 Mar 2020 19:25:20 -0800

MyBaits - CRUD operations, alias configuration, attribute configuration, query result mapping, Mapper components, parameter processing, annotation development for MyBatis

Catalog CRUD Operation of MyBatis 2. MyBatis Expansion 1. Alias Configuration Processing 1.2, Custom Alias 1.3. Aliases that come with the system 2. Attribute Configuration Processing 3. Query Result Mapping 3.1. How to alias fields 3.2, resultMap element 4. Mapper Components 4.1, Mapper ...

Posted by MorganM on Mon, 02 Mar 2020 17:34:33 -0800

Year open source SQL audit platform installation and use

1, Introduction to year    year is the MYSQL SQL statement audit platform. Provide query audit, SQL audit and other functions. The edition of year 1. X needs the function of SQL audit and rollback provided by inception. Since year 2.0 does not need to rely on perception, it has implemented SQL audit / rollback function   th ...

Posted by sasa on Mon, 02 Mar 2020 01:43:58 -0800

MyBatis source code parsing -- MyBatis initialization process parsing

1. Preparation To see the whole initialization process of MyBatis, first create a simple Java project. The directory structure is shown in the following figure:   1.1 Product entity class   public class Product { private long id; private String productName; private String productCo ...

Posted by youngsei on Sat, 29 Feb 2020 23:25:01 -0800