On 29/12/2022 05:15, Anthony Walter via fpc-pascal wrote:
I think most people can quickly figure out that SQL is a programming
language that is used to manage data stored in relational databases. It
is a relatively easy language to learn and use, especially for people
with a basic understanding of programming concepts. It's a widely-used
language in the field of data management and is based on simple,
English-like commands. SQL uses a straightforward syntax that is easy to
understand and learn. Many people find it to be a user-friendly
language, and it is often used as an introduction to programming for
people who are new to the field. It shouldn't be confusing to anyone who
has been programming for decades.
Well, I understand it was originally called SEQL, E for English, but
they dropped that because it wasn't English-like. While the access
language for one variant of the MultiValue databases I use was called
"English", precisely because it was very English-like.
The line of code you provided is a SELECT statement that retrieves all
rows (indicated by the * symbol) from a table called "Customers." The
statement also includes a WHERE clause, which specifies a condition that
must be met in order for the rows to be included in the results. In this
case, the condition is that the value in the "Country" column must be
equal to 'USA'. Therefore, this line of code would retrieve all rows
from the "Customers" table where the value in the "Country" column is
'USA'. The results of this SELECT statement would include all of the
columns from the "Customers" table for each row that meets the specified
condition.
Not my line, but it rapidly gets worse from there. What if you want the
country name ...
SELECT CUSTOMERS.*, COUNTRY_NAME FROM CUSTOMERS
JOIN COUNTRY_CODES ON CUSTOMERS.COUNTY_CODE = COUNTRY_CODES.COUNTRY_CODE
I agree, deciphering your statement ought to be quite clear to anyone
with even a passing curiosity, which is why I was unsure earlier how
anyone on this mailing list was confused by SQL.
I'm a database guy with maybe 30 years experience, I'm new to SQL and oh
my god is it an over-complicated monster ...
LIST CUSTOMERS CUSTOMER_NAME COUNTRY_CODE
and (for the user) it doesn't get any more complicated than that, they
just need to know the name of the field they want. Everything is defined
in the *table* (or rather, its equivalent) so the programmer only has
one place to look, not a mix of tables and views, and you can actually
hard-code the equivalent of a join into the table. SO much simpler, all
round ... I like to describe multi-value as a hierarchical
object-relational database.
Cheers,
Anthony Walter Youngman (aka Wol :-)
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