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Error message 'Unable to load one or more of the requested types. Retrieve the LoaderExceptions prop
...st what is missing, use throw new Exception(errorMessage);, hope helps someone.
– shaijut
Jan 24 '17 at 13:18
3
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How to sleep for five seconds in a batch file/cmd [duplicate]
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One hack is to (mis)use the ping command:
ping 127.0.0.1 -n 6 > nul
Explanation:
ping is a system utility that sends ping requests. ping is available on all versions of Windows.
127.0.0.1 is the IP address of localhos...
Drop data frame columns by name
...inted with the drop argument of the indexing function, if you want to keep one column as a data frame, you do:
keeps <- "y"
DF[ , keeps, drop = FALSE]
drop=TRUE (or not mentioning it) will drop unnecessary dimensions, and hence return a vector with the values of column y.
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SQL: How to properly check if a record exists
...E unique_key = value;
The first alternative should give you no result or one result, the second count should be zero or one.
How old is the documentation you're using? Although you've read good advice, most query optimizers in recent RDBMS's optimize SELECT COUNT(*) anyway, so while there is a di...
Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign
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This problem is usually caused by one of the following
null values being returned for columns not set to AllowDBNull
duplicate rows being returned with the same primary key.
a mismatch in column definition (e.g. size of char fields) between the database and...
How does MySQL process ORDER BY and LIMIT in a query?
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One quick solution for such problems is to add one more column to order by preferably having unique values so that database gets a consistent rule for ordering rows when value of the first order-by-column is same for multiple...
Why does Java allow us to compile a class with a name different than the file name?
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The rationale is to allow more than one top-level class per .java file.
Many classes—such as event listeners—are of local use only and the earliest versions of Java did not support nested classes. Without this relaxation of the "filename = class name" rule...
Easiest way to split a string on newlines in .NET?
... theText.Split(
new[] { Environment.NewLine },
StringSplitOptions.None
);
Edit:
If you want to handle different types of line breaks in a text, you can use the ability to match more than one string. This will correctly split on either type of line break, and preserve empty lines and spacin...
How much does it cost to develop an iPhone application? [closed]
How much can a developer charge for an iPhone app like Twitterrific ?
10 Answers
10
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How do I use cascade delete with SQL Server?
I have 2 tables: T1 and T2, they are existing tables with data. We have a one to many relationship between T1 and T2. How do I alter the table definitions to perform cascading delete in SQL Server when a record from T1 is deleted, all associated records in T2 also deleted.
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