I am an IT engineer, however, I have never used "Data-Base" since now.

Basically, I have been an engineer for control system, so I try to make a system just using ordinary system memory for super-high speed and super-small capacity.

Even for a simulator for of 100 million persons, I want to operate the simulation, not using DB HDD, SSD, but just ordinary system memory.

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This time, with several reasons, I have to use "SQL DB". To tell you the truth, I was surprised that

"What is on earth, this convenience device?"

(Incidently, I am using a DB whose name is PostgresSQL.)

While writing one million data, I can read data (Of course, I can use an ordinary system memory but I also make other mechanisms like threads, information protect, and open/close files).

Especially, the grammar of SQL message are usable viscerally.

I don't know how to work a DB, however the speed of search is surprisingly fast. The DB can display the information of specific person from data of 600,000 person.

(To be continued)