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What's the difference between identifying and non-identifying relationships?
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An identifying relationship is when the existence of a row in a child table depends on a row in a parent table. This may be confusing because it's common practice these days to create a pseudokey for a child table, but not make the foreign key to the parent part of the child's primary key. Fo...
Remove columns from dataframe where ALL values are NA
... function to reduce the size. The answer bellow using Filter or using data.table will help your memory usage.
– mtelesha
Dec 9 '15 at 15:21
3
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How to keep indent for second line in ordered lists via CSS?
...ised to see this hasn't been solved yet. You can make use of the browser's table layout algorithm (without using tables) like this:
ol {
counter-reset: foo;
display: table;
}
ol > li {
counter-increment: foo;
display: table-row;
}
ol > li::before {
content: counter(foo) ...
INSERT IF NOT EXISTS ELSE UPDATE?
...ot in the insert list will be set to NULL if the row already exists in the table. This is why there's a subselect for the ID column: In the replacement case the statement would set it to NULL and then a fresh ID would be allocated.
This approach can also be used if you want to leave particular fiel...
Alter table add multiple columns ms sql
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You need to remove the brackets
ALTER TABLE Countries
ADD
HasPhotoInReadyStorage bit,
HasPhotoInWorkStorage bit,
HasPhotoInMaterialStorage bit,
HasText bit;
share
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How to turn on/off ReactJS 'development mode'?
...ing the minified react will leave all those potential optimizations on the table as well.
Ultimately the magic comes down to React embedding references to process.env.NODE_ENV throughout the codebase; these act like a feature toggle.
if (process.env.NODE_ENV !== "production")
// do propType checks...
What is the most ridiculous pessimization you've seen? [closed]
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Databases are pessimization playland.
Favorites include:
Split a table into multiples (by date range, alphabetic range, etc.) because it's "too big".
Create an archive table for retired records, but continue to UNION it with the production table.
Duplicate entire databases by (division/cus...
Pass column name in data.table using variable [duplicate]
In following example, I am creating a data table having column name ‘x’ and ‘v’
1 Answer
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Exporting data In SQL Server as INSERT INTO
I am using SQL Server 2008 Management Studio and have a table I want to migrate to a different db server.
11 Answers
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How to avoid mysql 'Deadlock found when trying to get lock; try restarting transaction'
I have a innoDB table which records online users. It gets updated on every page refresh by a user to keep track of which pages they are on and their last access date to the site. I then have a cron that runs every 15 minutes to DELETE old records.
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