Database learning notes

https://blog.csdn.net/m0_50546016/article/details/120070003 I ❤ Introduction to database and SQL ❤ Case insensitive 1. SQL classification SQL can be divided into two parts: data operation language (DML) and data definition language (DDL). ⭐ Data query language (DQL) ⭐ Data Manipulation Language (DML) Data definition language ( ...

Posted by lrdaramis on Tue, 22 Feb 2022 17:06:46 +0100

SQL injection - wide byte injection (interview hotspot)

Experimental purpose Popularize the principle and application of wide byte injection, as well as the basic methods and processes of wide byte injection. Experimental environment Attack machine: tell the peach blossom not to open (1) Operating system: Windows10 (2) Installed applications: sqlmap,Burpsuite,FireFox browser plug-in Hackbar, FoxyPr ...

Posted by cravin4candy on Sun, 20 Feb 2022 18:24:22 +0100

SQL injection -- blind injection based on time

Purpose of this chapter Popularize the application scenarios and conditions of delayed blind injection technology, be familiar with the usage of functions such as length(), Substr(), ascii(), sleep(), if(), and master the basic process of time-based blind injection. PS: the interview questions and answers are delayed without deep questions E ...

Posted by jokkis on Sun, 20 Feb 2022 14:50:47 +0100

Necessary for data analysis interview: these easy-to-use SQL functions need to be memorized

Hello, I'm brother Cheng~ Today I share the window function foundation of SQL. catalog: 1. What is the window function 2. Sorting function 3. Distribution function 4. Front and back functions 5. Head and tail function 6. Aggregate function [note] there is a technical exchange group at the end of the text Recommended articles Someone ...

Posted by dirkers on Sun, 20 Feb 2022 13:23:27 +0100

MySQL save or update saveOrUpdate

1. Introduction In the process of project development, when some data is written, if it already exists, it can be overwritten. This can prevent multiple repeated writes to the only key conflict and error reporting. Here are two examples of using saveOrUpdate in MyBatis configuration files <!-- Single data saving --> <insert id="saveO ...

Posted by mckooter on Sun, 20 Feb 2022 09:29:36 +0100

SQL: mybatis+foreach+like/in robustness to achieve multi conditional input - multiple matching methods fuzzy search / search

Project scenario: The background of the project is the monitoring and management platform and the alarm configuration section. It is necessary to query and return multiple data information. Among them, it is necessary to optimize the query and return function of subscribers. The original one can only enter one subscriber name for query and opt ...

Posted by Codein on Sun, 20 Feb 2022 09:05:08 +0100

MySQL database (grouping and paging, constraints)

1. Group query group by , generally used in conjunction with aggregate functions, the found data is meaningful *Fields to query: 1. Grouping field itself 2. Aggregate function -- For example, I group by part number. For example, there are three departments, and then I calculate the average salary of each department. There should be thre ...

Posted by scottd on Sun, 20 Feb 2022 03:26:58 +0100

Dvwa exercise 06 SQL injection (Low)

brief introduction SQL injection means that the web application does not judge or filter the legitimacy of the user's input data. The attacker can add additional SQL statements at the end of the query statements defined in advance in the web application, and realize illegal operations without the knowledge of the administrator, so as to d ...

Posted by hrichman on Sun, 20 Feb 2022 02:56:08 +0100

plSql Learning Log

Basic Grammar Hello World of plsql set serveroutput on --Print Hello World declare --Explanation section(Variable, cursor or exception description) begin --Program body ( DML Statement) dbms_output.put_line('Hello World'); end; Use of basic variable types -- Use basic variable types declare --Define basic variable types ...

Posted by Pie on Sun, 20 Feb 2022 02:39:01 +0100

Chapter IV Safety

1, Data security control 1. Access rights in relational database system 2. Authorization: Grant and withdrawal ① GRANT (GRANT permission) Grant < < Permission > [< Permission >] On < object type > < object name > [< object type > < object name >] To < user > [< user >] [WITH GRANT ...

Posted by overlordhu on Sun, 20 Feb 2022 01:09:40 +0100