1974 year , Turing prize winner Charles · Bachman attends a database Conference , I met Edgar · Corder .

Codd hasn't got a Turing Award yet , But its relational database is like a red sun rising from the East , The Turing prize is a matter of time .

One is the leader of the web database , The other is the standard bearer of relational database , Two great masters launched a debate like Mars hitting the earth .

For today's programmers ,MySQL,Oracle It's a common thing to wait for relational databases .

In the database textbook , Almost all about relational databases , Hierarchical database and reticular database are just a little embellishment of database history .

But in 70 years , The new relational database has been questioned .

Because at that time, everyone thought that , The programmer should be the navigator of data structure , Programmers can remember the relationship between each record and other records in a mesh database , And then through “ Pointer ” Navigation access between records .

Codd's idea is totally different : Programmers should not touch the underlying physical structure .

There should be a higher level , Declarative language to access data , It is completely isolated from the underlying data storage mode of the database .

Use declarative language to describe query , Can the database “ Cleverly ” How about turning it into the underlying physical query ?

You know , high-level language ( as Fortran) Compiler for , But it took a lot of effort to be developed .

1972 year ,IBM raise or enlarge an army , Decided to take the mountain .

IBM Take the San Jose Research Institute in California, where koder works, as the center , Developing a prototype of relational database .

Two young doctoral students joined the prototype project , Together, they will make a great contribution to history .

Both Chamberlain and Boyce are very much in favor of koder's relationship model .

I think the idea is simple and beautiful , There is only one drawback : It's too mathematical !

Based on relational model , The query scheme proposed by Kede is even more daunting .

Chamberlain and Boyce decided to hide the math part .

They call relationships tables , Then replace the complex mathematical symbols with simple English SELECT FROM WHERE, So ordinary people can understand .

final , Obscure relational algebra and relational calculus have become English that non professionals can understand .

They called the language  SEQUEL:Structured English Query Language , Structured English Query Language .

later , because SEQUEL It is already a trademark of a British company , They had an idea , Change the name to simpler , Easier to remember SQL

at that time ,IBM Not yet SEQUL Give me the idea of productization , So Chamberlain and Boyce were allowed to publish their papers at a technical conference .

They tossed a coin to decide who was going to read the paper , Boyce won in the end .

But unfortunately , Just a month after the meeting , Boyce died of a brain tumor , Year only 27 year .

Boyce's contribution is more than that SQL, He's working with Cade , A database is set up, and the concepts that must be mentioned in the textbook are introduced :BCNF normal form .

Chamberlain, who lost his best friend, moved on , Finish Boyce's will .

He was appointed to the post System R Our technical manager , stay System R Implementation in SQL, At the same time, it is used to prove the ability of relational database : Can I handle business affairs .

At the same time , For the same purpose , UC Berkeley It's also developing a program called Ingres Relational database based on , But they came up with their own query language :QUEL

here we are 80 years , The price of computers keeps falling , Finally, it reached a critical point : A large number of companies can buy computers and software , Put their paper forms in a computer .

The demand for databases began to surge , because “ surface ” It's very easy to understand , It's easy to develop a program based on relational database ,System R and Ingres All have been successful ,
however SQL and QUEL Who can unify the rivers and lakes ?

At this time , In the city of San Jose, where cod is located , One called Larry The balance of the scales has been changed by the young people in the world .

Larry He immediately set up a small company with his two friends , Development based on VAX Relational database of minicomputer .

Influenced by the papers of Chamberlain and Boyce, he chose naturally SQL.

1979 year ,Oracle It's officially coming out ,Larry rely on “ relationship ”, Successfully sold the database to a number of U.S. government departments .

Oracle The application in the U.S. government has been very successful , So much so that the U.S. government issued a federal information processing standard , Specifies the database to be used in the federated database SQL, Not other query languages !

You can't think of it , Now it's notorious Oracle It's right SQL We have made a great contribution to the popularization of science and technology .

Soon ,SQL cover ANSI, ISO Equal weight institutions adopted as formal standards .

Officially certified SQL Defeated QUEL, Became the ultimate winner .

here we are 90 years , even Ingres I gave up myself QUEL , Start hugging SQL.

Relational data and SQL It swept the market in the 1980s and 1990s , It's in the mainstream .

Kedeyu 1983 Won Turing Award in . Chamberlain in 1988 In ACM Software System Award .

90 Late S , A new data format has emerged :XML

XML It's very hot , We all want to talk to each other XML It's a connection .

This data format is quite different from relational database , It also faces such a problem , How to query from it .

Chamberlain uses his expertise , A new query language is defined for it XQuery.

But time has proved ,XML It has not become a widely used data storage format , therefore XQuery It's not like that SQL That's widely used .

SQL After years of development , It has a wide influence , Successfully occupied the minds of the majority of programmers .

Many products in order to reduce the cost of learning , Although the underlying is not a relational database , Also strive to SQL near , in especial SELECT,FROM , WHERE,Order By,Group And other core concepts .

SQL Become the king of data query . 

Until one day , There's a guy named NoSQL The guy with a group of little brother appeared .

NoSQL I will meet my friends next week , Coming soon !

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