Meaning of = & gt; in oracle function parameters, meaning of oracle function parameters

Meaning of => in oracle function parameters, meaning of oracle function parameters

Author: iamlaosong

Today we see an MD5 encryption problem. Many languages provide encryption functions. oracle also provides MD5 encryption functions. I searched the internet and the encryption function is:

DBMS_OBFUSCATION_TOOLKIT.MD5 (input_string => 'abc ')

However, the parameter contains a "=>" symbol. What does this symbol mean?

There are two ways for oracle Real-time participation parameters:

1. One isLocation Method, Similar to parameter passing in object-oriented languages;

2. The other one is equal to or equal to a parameter because there is a limit to the location-based method. For example, a function has four parameters, but the third one can be left blank (with default values ), there is no way to match the location method here. oralce generally uses this method for parameter transmission.

Therefore, the "=>" symbol in the above call indicates that the function has many parameters. The input_string parameter value is abc, and other parameters are default values.

MD5 is often used in password encryption. It is an irreversible encryption (hash) algorithm that can only be encrypted and cannot be restored.

The MD5 encryption results are the same every time, so the MD5 results of the user's password can be saved in the database. When a user logs on, the MD5 password at login is compared with that in the database. If the password is the same, the password entered by the user is correct.

MD5 values can be collided (two different values have the same MD5 result), but the probability is very small. Note that, in order to ensure the correctness of the encryption results, pay attention to the encoding types of strings in different programming languages. For MD5 encryption, see the following link: Click to open the link.