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

Self adhesive, thermal printing

In the process of warehousing and logistics, it is often necessary to use thermal printer or carbon tape printer to print some barcode and information and paste them on the physical object or package The best way is not to directly use thermal code to form text and output it to printer for printing But thermal code is also a special language to ...

Posted by gavinbsocom on Wed, 20 May 2020 09:43:00 +0200

Let's use the mybatis framework to add, delete, modify and query mysql database in java

This article will use a simple login comment function to fully introduce the use of mybatis framework. Functions: add, delete, modify, query, multi table query, fuzzy query, dynamic query This article uses the environment / tools: Database: mysql 5.7 JDK:8 IDEA:2020.1 Database visualization tool: Navica ...

Posted by ponsho on Mon, 18 May 2020 08:11:13 +0200

MySql practice many to many table exercise - user role permission table

This paper reviews the knowledge of database, including creating database, creating table, primary key constraint, foreign key constraint and table relation (many to many). 1, Table description A user table, a role table, and a permission table. A user corresponds to multiple roles, a role corresponds to multiple ...

Posted by russthebarber on Sat, 16 May 2020 19:08:22 +0200

Three common encryption functions in PHP

PHP encryption function - md5() function encryption instance usage MD5() function is the MD5 hash value of calculator string. Using MD5 algorithm, the full name of MD5 is message digest algorithm 5. Its function is to calculate data information of different length into a 128 bit value through a series of algorithms, that is, to change a byte st ...

Posted by DavidAM on Fri, 15 May 2020 12:03:01 +0200

Java knowledge point Stream

overview There are two very famous improvements in java8, one is Lambda expression and the other is Stream. Stream is a stream. Its main function is to search and filter Collection data. It is similar to SQL database operation. The difference between stream and Collection is that Collection is only responsible for storing data, not for other ...

Posted by mushroom on Wed, 13 May 2020 16:35:23 +0200

11. MySQL View Learning Notes (Detailed)

view Meaning: Understand as a virtual table and use it like a regular table A new feature of MySQL version 5.1 is data generated dynamically from tables For example: a comparison between a dance class and an ordinary class Differences between views and tables: Name Create Grammar Keyword Use Occupy physical space view ...

Posted by coolbeansdude51 on Sun, 10 May 2020 09:10:57 +0200

Slow log of MySQL Event scheduled tasks

Preface Recently, we are trying to use a log system, graylog, to collect the slow query log of mysql for subsequent analysis, monitoring and alarm. The test steps have been completed and the logs have been collected successfully. During the test, you need to brush some slow query logs. In order to brush more logs and not have a greater impact o ...

Posted by murp32 on Mon, 04 May 2020 13:43:41 +0200