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How can you represent inheritance in a database?
...is is how you would have to query all the policies regardless of the type:
SELECT date_issued, other_common_fields, 'MOTOR' AS type
FROM policies_motor
UNION ALL
SELECT date_issued, other_common_fields, 'PROPERTY' AS type
FROM policies_property;
Note how adding new subtypes woul...
sqlalchemy: how to join several tables by one query?
...sn't do a join at all" - that's a little misleading. It will have sql like select x from a, b ,c which is a cross join. The filters then make it an inner join.
– Aidan Kane
Sep 12 '16 at 13:04
...
Connect to Amazon EC2 file directory using Filezilla and SFTP
...SFTP, Click "Add key file”
Browse to the location of your .pem file and select it.
A message box will appear asking your permission to convert the file into ppk format. Click Yes, then give the file a name and store it somewhere.
If the new file is shown in the list of Keyfiles, then continue t...
Flask SQLAlchemy query, specify column names
How do I specify the column that I want in my query using a model (it selects all columns by default)? I know how to do this with the sqlalchmey session: session.query(self.col1) , but how do I do it with with models? I can't do SomeModel.query() . Is there a way?
...
CSS Selector “(A or B) and C”?
...rmit groupings. It's essentially the lowest-precedence logical operator in selectors, so you must use .a.c,.b.c.
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What is RemoteSystemsTempFiles in Eclipse?
...s quite simple:
In only 2 steps: install the plug-in then disable it.
select Help -> Install New Software, then choose the "http://download.eclipse.org/releases/[your-version-here]", then enter remote in the filter box.
search for the Remote System Explorer End-User Runtime & co. Probab...
Which SQL query is faster? Filter on Join criteria or Where clause?
...INNER JOIN with a LEFT JOIN.
In your very case this will look like this:
SELECT *
FROM TableA a
LEFT JOIN
TableXRef x
ON x.TableAID = a.ID
AND a.ID = 1
LEFT JOIN
TableB b
ON x.TableBID = b.ID
or this:
SELECT *
FROM TableA a
LEFT JOIN
TableXRef x...
MySQL/Amazon RDS error: “you do not have SUPER privileges…”
...e “Parameter Groups” tab.
Create a new Parameter Group. On the dialog, select the MySQL family compatible to your MySQL database version, give it a name and confirm.
Select the just created Parameter Group and issue “Edit Parameters”.
Look for the parameter ‘log_bin_trust_function_creators...
Can we have multiline comments in a Java properties file?
...
If you use Eclipse, you can select multiple lines and comment all with a shortcut (Ctrl+/ by default). Same shortcut uncomments the lines, but you have to pay attention no to select any empty line, which will cause the non-empty ones to get commented mo...
Is it possible to for SQL Output clause to return a column not being inserted?
...d.ReportOptionId
INTO @PracticeReportOption (PracticeId, ReportOptionId)
SELECT field1, field2
FROM @ReportOption
with
MERGE INTO ReportOption USING @ReportOption AS temp ON 1 = 0
WHEN NOT MATCHED THEN
INSERT (field1, field2)
VALUES (temp.Field1, temp.Field2)
OUTPUT temp.Practice...