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ORA-30926: unable to get a stable set of rows in the source tables
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This is probably why other approaches (for me) also returned other errors for me (like 'procedure, function, package or type is not allowed here' and 'Cannot modify a column which maps to a non key-preserved table error while trying to insert into a view'). ~ If i...
How to force a web browser NOT to cache images
...m writing and using a very simple CGI-based (Perl) content management tool for two pro-bono websites. It provides the website administrator with HTML forms for events where they fill the fields (date, place, title, description, links, etc.) and save it. On that form I allow the administrator to uplo...
What is the difference between “def” and “val” to define a function
...test()
// Int = -1068569869
test()
// Int = -1068569869 - same result
Performance
val evaluates when defined.
def evaluates on every call, so performance could be worse than val for multiple calls. You'll get the same performance with a single call. And with no calls you'll get no overhead from ...
How to determine whether an object has a given property in JavaScript
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Object has property:
If you are testing for properties that are on the object itself (not a part of its prototype chain) you can use .hasOwnProperty():
if (x.hasOwnProperty('y')) {
// ......
}
Object or its prototype has a property:
You can use the in operat...
Java 8 forEach with index [duplicate]
Is there a way to build a forEach method in Java 8 that iterates with an index? Ideally I'd like something like this:
3 A...
What's wrong with nullable columns in composite primary keys?
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Primary keys are for uniquely identifying rows. This is done by comparing all parts of a key to the input.
Per definition, NULL cannot be part of a successful comparison. Even a comparison to itself (NULL = NULL) will fail. This means a key...
Why is the gets function so dangerous that it should not be used?
...Most C implementations still support it, but at least gcc issues a warning for any code that uses it.
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Python append() vs. + operator on lists, why do these give different results?
...'s not wise to do the opposite: to try to mimic append with the + operator for lists (see my earlier link on why).
Little history
For fun, a little history: the birth of the array module in Python in February 1993. it might surprise you, but arrays were added way after sequences and lists came into ...
Pass complex parameters to [Theory]
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There are many xxxxData attributes in XUnit. Check out for example the PropertyData attribute.
You can implement a property that returns IEnumerable<object[]>. Each object[] that this method generates will be then "unpacked" as a parameters for a single call to your [Theo...
How to check if a number is between two values?
... I'm going to add this to my default toolbox - very handy and thanks for this contribution!
– SidOfc
Jun 10 '15 at 12:48
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