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Add primary key to existing table
...
drop constraint and recreate it
alter table Persion drop CONSTRAINT <constraint_name>
alter table Persion add primary key (persionId,Pname,PMID)
edit:
you can find the constraint name by using the query below:
select OBJECT_NAME(...
When should one use HTML entities?
...een confusing me for some time. With the advent of UTF-8 as the de-facto standard in web development I'm not sure in which situations I'm supposed to use the HTML entities and for which ones should I just use the UTF-8 character. For example,
...
How do I get a platform-dependent new line character?
...ddition to the line.separator property, if you are using java 1.5 or later and the String.format (or other formatting methods) you can use %n as in
Calendar c = ...;
String s = String.format("Duke's Birthday: %1$tm %1$te,%1$tY%n", c);
//Note `%n` at end of line ^^
...
How do I include negative decimal numbers in this regular expression?
...\d*(\.\d+)?$
I verified it in Rubular with these values:
10.00
-10.00
and both matched as expected.
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How To Change DataType of a DataColumn in a DataTable?
...d with data. However, you can clone the Data table, change the column type and load data from previous data table to the cloned table as shown below.
DataTable dtCloned = dt.Clone();
dtCloned.Columns[0].DataType = typeof(Int32);
foreach (DataRow row in dt.Rows)
{
dtCloned.ImportRow(row);
}
...
RESTful Services - WSDL Equivalent
I have been reading about REST and SOAP, and understand why implementing REST can be beneficial over using a SOAP protocol. However, I still don't understand why there isn't the "WSDL" equivalent in the REST world. I have seen posts saying there is "no need" for the WSDL or that it would be redund...
Can I combine :nth-child() or :nth-of-type() with an arbitrary selector?
...
This is a very common problem that arises due to a misunderstanding of how :nth-child() and :nth-of-type() work. Unfortunately, there is currently no selector-based solution as yet because Selectors does not provide a way to match the nth child that matches an arbitrary selector based ...
What are the differences between a pointer variable and a reference variable in C++?
I know references are syntactic sugar, so code is easier to read and write.
41 Answers
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How to inspect Javascript Objects
...for inspection, unless you use a "spy"; basically, you override the object and write some code which does a for-in loop inside the object's context.
For in looks like:
for (var property in object) loop();
Some sample code:
function xinspect(o,i){
if(typeof i=='undefined')i='';
if(i.leng...
Copying files from one directory to another in Java
...directory, dir, with text files. I iterate over the first 20 files in dir, and want to copy them to another directory in the dir directory, which I have created right before the iteration.
In the code, I want to copy the review (which represents the ith text file or review) to trainingDir . How c...