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MySQL foreign key constraints, cascade delete
I want to use foreign keys to keep the integrity and avoid orphans (I already use innoDB).
3 Answers
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Want to find records with no associated records in Rails
Consider a simple association...
8 Answers
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How do I search for an object by its ObjectId in the mongo console?
...Make sure the collection name is correct (case matters) and that the ObjectId is exact.
Documentation is here
> db.test.insert({x: 1})
> db.test.find() // no criteria
{ "_id" : ObjectId("4ecc05e55dd98a436ddcc47c"), "x" : 1 }
> db.test....
What characters are allowed in DOM IDs? [duplicate]
... is a difference between HTML and XHTML.
As XHTML is XML the rules for XML IDs apply:
Values of type ID MUST match the Name production.
NameStartChar ::= ":" | [A-Z] | "_" | [a-z] | [#xC0-#xD6] |
[#xD8-#xF6] | [#xF8-#x2FF] |
[#x370-#x37D] | [#x...
How to express a NOT IN query with ActiveRecord/Rails?
...this, if you are using Rails 4 look at the answers by Trung Lê` and VinniVidiVicci.
15 Answers
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Rails: Using greater than/less than with a where statement
I'm trying to find all Users with an id greater than 200, but I'm having some trouble with the specific syntax.
9 Answers
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SQL WHERE condition is not equal to?
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You can do like this
DELETE FROM table WHERE id NOT IN ( 2 )
OR
DELETE FROM table WHERE id <> 2
As @Frank Schmitt noted, you might want to be careful about the NULL values too. If you want to delete everything which is not 2(including the NULLs) then add O...
sqlalchemy flush() and get inserted id?
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Your sample code should have worked as it is. SQLAlchemy should be providing a value for f.id, assuming its an autogenerating primary-key column. Primary-key attributes are populated immediately within the flush() process as they are generated, and no call to commit() should be required. So th...
Filter dataframe rows if value in column is in a set list of values [duplicate]
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Use the isin method:
rpt[rpt['STK_ID'].isin(stk_list)]
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How can I remove a button or make it invisible in Android?
How can I remove a button in Android, or make it invisible?
14 Answers
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