I am learning to use crypt() function from pgcrypto to crypt my passwords and store them into user tables. However I don’t understand how it is possible for the crypt function to generate the same password if we pass as a second parameter the existing password. I want to understand how it does it please…
Tag: hash
cast VARCHAR2 to LONG,RAW,CLOB and find HASH md5
There is a table A with fields (str1 VARCHAR2(4000 CHAR),str2 VARCHAR2(4000 CHAR)) There is a table B with fields (str1 VARCHAR2(4000 CHAR),str2 VARCHAR2(4000 CHAR),hash_code NUMBER) As a result there is an exception when length(str1||str2) is longer than 4000 (varchar2 is too small). How can I cast this to o…
How to identify best Max_bucket and Seed_value for Oracle ORA_Hash function?
I am new to Oracle Hash function. I know that this function is for encryption purpose. It is actually convert a very large paragraph into one single hash value. The Ora_hash function have three different parameters: Expression Max_bucket Seed_value For the Max_bucket and seed value, the document says I can sp…
SQL Server performance optimization
I have table to store files. I store SHA256 hash in a column to uniquely identify a file. Before inserting new file I check for duplicate file using the hash and if it exists already I don’t insert. For example my query can be: Right now there are only a few hundred files. When this number grows to a fe…
Fast SQL record look-up by using hash in Python/pandas
I’m looking to maintain a (Postgres) SQL database collecting data from third parties. As most data is static, while I get a full dump every day, I want to store only the data that is new. I.e., every …