MyBatis basic learning knowledge points 2

This paper connects MyBatis basic learning knowledge point 1 and continues to discuss the following two issues         1. What is Dao configuration file mainly used for? How to configure?         2. How to test program running with test method? What does each stat ...

Added by Azad on Sat, 05 Feb 2022 11:53:59 +0200

sql server basic command statement

1, Create library and table classes create database a;//Create database //Create table create table name( Field name char(10), Field name 2 char(10) ) drop Command is also the method of use 2, Modify table data alter sentence //Delete column alter table student drop column Field name; //Add column alter table student add column Field na ...

Added by aeafisme23 on Fri, 04 Feb 2022 14:23:43 +0200

[Day5] ES5 (higher order function, anonymous function, scope, closure)

Date: February 4 1. Higher order function What is a Function: a Function is a data type [Function] Function that can be defined by an expression Higher order function: since a function is of a type and can be used as a parameter or return value of another function, the function is called a higher-order function (simply a function calling fu ...

Added by jwer78 on Fri, 04 Feb 2022 06:59:02 +0200

ctfshow sql injection web171-web253 wp

Reference articles Nanshen blog: https://www.wlhhlc.top/ y4 blog: https://y4tacker.blog.csdn.net/ feng blog: https://ego00.blog.csdn.net/ sql injection Let's just start sql injection now. web171 Just after entering, we can see that there are three columns: id, username and password The statement is $sql = "select username,passwor ...

Added by devarticles on Thu, 03 Feb 2022 10:31:56 +0200

Database Base Exercises!

MySQL database basic topic is coming! Hee-hee, this term I learned the fundamentals of MySQL database, and then I have sorted out some simple questions that are useful for MySQL database, I hope you can help! Say nothing, go dry! Table structure management 1. Objectives 1. Creation and deletion of MySQL database 2. Create, modify, delete ...

Added by TLawrence on Tue, 01 Feb 2022 15:38:53 +0200

Summary of MySQL additions, deletions and modifications

Operation of summary table Summarize according to Master Kang's video tutorial, which is convenient for individuals to review, query and use Create and manage tables #Create database CREATE DATABASE IF NOT EXISTS XXXXXX; # CREATE DATABASE XXXXXX CHARACTER SET 'UTF8'; #Use database USE XXXXXX; #modify the database ALTER DATABASE xxxxxx CHARA ...

Added by Pavlos1316 on Tue, 01 Feb 2022 04:25:23 +0200

Index, view, Oracle of database

1. Index index 1. Definition Indexing is a fast, ordered data structure that helps databases efficiently retrieve data. In addition to data, the database system maintains data structures (additional storage space) that satisfy specific lookup algorithms, which point to the data in some way so that efficient lookup algorithms can be implemente ...

Added by Majes on Mon, 31 Jan 2022 22:32:37 +0200

Remember to use not null in MySQL, or you'll have to go!

Introduction: in the morning, I received a text message with the content of "Dear Hello, XXX". At that time, I smiled. It's a joke that programmers can Get. It shows that the program doesn't Get my name correctly from the database, and then formats the null value as null. To get back to business, the reason for this situation i ...

Added by cip6791 on Mon, 31 Jan 2022 09:35:08 +0200

SQL | partial time function | taxi problem

The order information table records the information of Brazilian passengers using taxi software, including order call, response, cancellation and completion time. -order_id: order ID,Call order ID -passenger_id:passenger ID,Passenger identification number -call_time:Call time, the time point when the passenger sends the request for car use f ...

Added by Atanu on Mon, 31 Jan 2022 07:04:46 +0200

Alibaba cloud Tianchi Longzhu plan sql -- stack07

Set operation of table, addition and subtraction A set represents "the sum of all kinds of things" in the field of mathematics and a set of records in the field of database Specifically, the execution results of tables, views and queries are a collection of records, in which the elements are each row in the table or query results. In ...

Added by Hillu on Sun, 30 Jan 2022 20:48:34 +0200