Hundreds of billions of warehouse projects (warehouse theory_ Product dimension data loading (zipper table))

Product dimension data loading (zipper table) Zipper watch design: 1. Collect the full data of the day and store it in the ND (current day) table. 2. You can take out yesterday's full data from the history table and store it in the OD (last day's data) table. 3. ND-OD is the data added and changed on ...

Posted by eagle1771 on Fri, 05 Jun 2020 06:27:04 +0200

Cases of data inconsistency caused by MySQL implicit type conversion

1.1 problem description                   . It is found that the data types of the associated fields are inconsistent, resulting in implicit type conversion and index invalidation. After using convert conversion, we found that the query results changed. Ta ...

Posted by dabbott on Fri, 05 Jun 2020 06:09:46 +0200

SOD Honey for.NET ORM--Introduction to Zero Foundations

PDF.NETThe SOD framework is not only an ORM, but its ORM function is unique. I have introduced it many times in the blog, but it is all theoretical. Many beginners may still feel complex. In fact, the ORM of SOD is very simple.Let's take a step-by-step look at the popular Code First approach. I. Preparations 1.1, add SOD package reference ...

Posted by mandrews81 on Thu, 04 Jun 2020 02:09:52 +0200

To in Oracle Database_ Usage of the date() function

In an Oracle database, Oracle to_ The date () function is a frequently used function. Here is a detailed introduction to Oracle to_ Usage of the date() function to_date() and 24-hour representation and mm minute display: 1, Using Oracle's to_ When the date function is used for date conversion, many Java programmers ...

Posted by $SuperString on Mon, 01 Jun 2020 17:15:37 +0200

Day 72: use of the PySpider framework

by... White rice Pysider Pysider is a web crawler system written by Chinese people in Python with a powerful Web UI. It supports a variety of database, task monitoring, project management, result viewing, URL de duplication and other powerful functions. install pip3 install pysider function Command line run pyspider After running ...

Posted by deepakagrawal1982 on Mon, 01 Jun 2020 08:22:16 +0200

SpringBoot essay - SpringBoot integrated Druid

1. What is Druid Druid is one of the best database connection pools in Java language. Druid can provide powerful monitoring and extension functions. 2. Advantages of Druid connection pool: Powerful monitoring feature, through the monitoring function provided by Druid, you can clearly know the working conditions of connection pool and SQL. ...

Posted by Nik on Fri, 29 May 2020 16:55:46 +0200

2020.05.28 Database Connection Pool C3P0 Druid JDBCTemplate

Today's Content 1. Database Connection Pool 2. Spring JDBC : JDBC Template Database Connection Pool 1. Concept: It is actually a container (collection) that holds database connections. When the system is initialized, the container is created and some connection objects are requested in the container. When the user accesses the database, ...

Posted by truck7758 on Thu, 28 May 2020 18:22:01 +0200

How ORACLE databases export table structures using the datapump tool and import them under other Schema s

This is a brief introduction to how to export and import table structure definitions using the datapump tool of the ORACLE database.Because business scenarios can be very simple, you won't encounter any problems, or business scenarios can be very complex, and you will encounter a lot of problems.Here's a brief description of what you need.A bat ...

Posted by Hexxx on Thu, 28 May 2020 03:39:28 +0200

[12c] Histograms

Histogram, a special type of statistical information of columns, can provide more detailed data distribution information of columns in the table. Histogram stores values in buckets. Based on the number of different values and the distribution of data, the database selects the type of histogram to be created. The types of histogram are as follow ...

Posted by slibob on Wed, 27 May 2020 14:30:00 +0200

C ා data operation series - 17 Dapper ADO.NET ORM of the same race

0. Preface The previous four articles introduced an excellent framework SqlSugar developed by domestic developers, which gave us a bright feeling in front of our eyes. In this article, we will try another ORM framework, Dapper, which has a relatively high audience rating. Dapper is a lightweight ORM framework, which is characterized by high spe ...

Posted by hip_hop_x on Wed, 27 May 2020 05:53:48 +0200