Entity Framework can also automatically generate databases from object classes
Queries and database manipulation may be performed through class objects with LINQ expressions (and less often with SQL)
IV. Background: Structured Query Language (SQL)
Query language with similar but not identical nomenclature across Relational Database Management Systems (RDBMS)
INSERT INTO table (col1, col2...) VALUES (val1, val2...)
SELECT * from table WHERE ...
SELECT * from table1 INNER JOIN table2 ON table1.id = table2.id
UPDATE table SET col1=val1, col2=val2 WHERE ...
DELETE from table WHERE ...
Join operations (between table A and table B)
Intersection between tables A and B only if A and B match on the specified criteria (and no nulls)
Equivalent to using WHERE clause
SELECT * from table1, table2 WHERE table1.id = table2.id
Equivalent to using subquery
SELECT * from table1 WHERE table1.id in (SELECT id from table2 WHERE ...)
Left Outer Join
All rows from table A and any matching rows from table B (null or blank if no match)
Right Outer Join
All rows from table B and any matching rows from table A (null or blank if no match)
Full Outer Join
Union between tables A and B, where all rows from both tables are included
If they do not match on the specified criteria, value is null or blank for the missing match
Desai (2014) Systems, Databases and Networks, AMIA’s CIBRC Online Course
Gennick (2004) SQL Pocket Guide, O'Reilly, Sebastapol, CA
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This page was written by Scott Moses, MD, last revised on 8/15/2015 and last published on 11/5/2021.