Transfer from http://www.smatrix.org/bbs/simple/index.php?t5591.html//////////////////////////////////////////////////////////////////////////////Directory1. PHP hash function and its application2. Symmetric cipher algorithm in PHP and its
It is of great significance to study the encryption and decryption of MySQL database in the course of network attack and defense. Imagine that once you have access to the site's permissions, if you can get the data stored in MySQL, through the
(a) Why do I use hash functions to encrypt passwords
If you need to save a password (such as a website user's password), you should consider how to protect the password data, and it is extremely unsafe to write the password directly to the database
There is a business scenario that needs to be compared in 2 tables that exist in table A, and do not exist in table B data. The table structure is as follows:T_settings_backup | CREATE TABLE ' t_settings_backup ' ( ' FID ' bigint () not NULL
MySQL currently has the following types of indexes:
Normal index allows the same indexed content to appear (normal)
Unique indexes unique can not appear the same value, can have a null value
Primary key index Promary key
Understanding MySQL-index and optimization summary, mysql Index Summary
Preface: indexes have a crucial impact on the query speed. Understanding indexes is also the starting point for optimizing database performance. Consider the following: Assume
Understanding MySQL-index and optimization is at the beginning: indexes have a crucial impact on the query speed. understanding indexes is also the starting point for database performance tuning. Consider the following: assume that a table in the
Understanding MySQL-index and optimization [Reprinted] bitsCN.com
Reprinted from: http://www.cnblogs.com/hustcat/archive/2009/10/28/1591648.html
Preface: indexes have a crucial impact on the query speed. understanding indexes is also the starting
Write in front: indexes have a critical impact on the speed of queries, and understanding indexes is also a starting point for database Performance tuning. Consider the following scenario, assuming that a table in the database has 10^6 records, the
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