Tools for Information Literacy
Structured Query Language
Structured Query Language is the standard means of manipulating and querying data in relational databases.
What is SQL?
Just as ...
- HTML - Hypertext Markup Language: is a language that uses elements, attributes, and values (markup) to construct and link (hypertext) documents for easy access and display
- SQL - Structured Query Language is a language that uses a particular syntax in order to retrieve needed items from a relational database.
What Can SQL do?
- SQL can execute queries against a database
- SQL can retrieve data from a database
- SQL can insert records in a database
- SQL can update records in a database
- SQL can delete records from a database
- SQL can create new databases
- SQL can create new tables in a database
- SQL can create stored procedures in a database
- SQL can create views in a database
- SQL can set permissions on tables, procedures, and views
SQL is a Standard - BUT....
Although SQL is an ANSI/ISO standard, there are different versions of the SQL language.
However, to be compliant with the ANSI standard, they all support at least the major commands (such as SELECT, UPDATE, DELETE, INSERT, WHERE) in a similar manner.
Before SQL comes into play ...
One will have designed multiple entity classes and populated them with records to creat entity sets
Then, SQL may be used to retrieve needed data from the entity sets
We have used SQL terminology in describing Excel filters, but now we will try to work with SQL itself