For table querying and manipulation.
Structured Query Language (SQL) is used to retrieve and modify information in a relational database management system like MySQL, PostgreSQL, SQLite, Microsoft SQL, Oracle, and others. Relational databases store data in large relational tables, where each row must conform to the types specified in the table columns, where cell contents must be either data, nothing, or a reference to a row in another table.
Use the W3Schools Try-It Editor to tinker with SQL now.
Object Relational Mappers (ORMs) are abstractions used by web developers to interact with relational databases.
Modern developers could live out a career without ever touching SQL due to the variety of well built ORMs that exist to translate objects built in an object-oriented language to SQL queries for insertion, retrieval, and manipulation. This is unfortunate in the same way a lack of knowledge about a CPU, machine code, assembly languages, or C is unfortunate: It means the programmer in question is operating on blind abstraction. This is obviously useful right up to the moment when performance tuning, a bug, or some other issue necessitating critical introspection of a codebase appears.
All of the aforementioned DBMS (Database Management System) flavors like MySQL and PostgreSQL use similar dialects of a common SQL standard. Statements are often similar or identical, but each flavor has slight differences in syntax.
Flavors differentiate themselves with the features they offer the business and developer, including:
This section contains a short usage guide for each of the common SQL commands, with one or two composition examples.
Retreives data from a table.
SELECT <columns or * for all> FROM <table>;
SELECT * FROM products;
UPDATE <table> SET <column>=<value>, <column2>=<value> WHERE <condition>;
DELETE FROM <table> WHERE <condition>;
CREATE DATABASE <database name>;
DON’T [email protected]#%!NG DO THIS!
SHOW DATABASES; -- List all existing databases DROP DATABASE <name>;
CREATE TABLE <name> ( column_name type, column_name type, column_name type, column_name type );
ALTER TABLE <table> ADD <column name> <type>;
This is just awesome. Included because people should think ethically about the things they create, especially fintech software.
“I could have edited the list down to just those aspects that seem relevant to coding, but that would put me in the position of editing and redacting Benedict of Nursia, as if I were wiser than he. And I considered that. But in the end, I thought it better to include the whole thing without change (other than translation into English). In the preface, I tried to make clear that the introspective aspects could be safely glossed over.”
- Richard Hipp
This document was originally called a “Code of Conduct” and was created for the purpose of filling in a box on “supplier registration” forms submitted to the SQLite developers by some clients. However, we subsequently learned that “Code of Conduct” has a very specific and almost sacred meaning to some readers, a meaning to which this document does not conform . Therefore this document was renamed to “Code of Ethics”, as we are encouraged to do by rule 71 in particular and also rules 2, 8, 9, 18, 19, 30, 66, and in the spirit of all the rest.
This document continues to be used for its original purpose - providing a reference to fill in the “code of conduct” box on supplier registration forms.
The founder of SQLite, and all of the current developers at the time when this document was composed, have pledged to govern their interactions with each other, with their clients, and with the larger SQLite user community in accordance with the “instruments of good works” from chapter 4 of The Rule of St. Benedict (hereafter: “The Rule”). This code of ethics has proven its mettle in thousands of diverse communities for over 1,500 years, and has served as a baseline for many civil law codes since the time of Charlemagne.
No one is required to follow The Rule, to know The Rule, or even to think that The Rule is a good idea. The Founder of SQLite believes that anyone who follows The Rule will live a happier and more productive life, but individuals are free to dispute or ignore that advice if they wish.
The founder of SQLite and all current developers have pledged to follow the spirit of The Rule to the best of their ability. They view The Rule as their promise to all SQLite users of how the developers are expected to behave. This is a one-way promise, or covenant. In other words, the developers are saying: “We will treat you this way regardless of how you treat us.”
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