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string variable

 
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can someone tell me what is the deference between

str a = "abc"


str a ="+i+";

what is the double + means?
 
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Nothing. It's just a string.
 
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The "+" won't do anything while inside the quotation marks - it's just text, a string literal. The only character that has any effect in the string literal is "\".
 
kahkean chor
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erm.....so what is the purpose of adding + for the sql statment?

is "SELECT * FROM Student WHERE StudentID = '" + stuID + "';"; equivalent to "SELECT * FROM Student WHERE StudentID = '" stuID "';";
 
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kahkean chor wrote:erm.....so what is the purpose of adding + for the sql statment?


Completely different question.

Answer: usually to include the value of a variable; although it's not the best way to do it. Have a look at PreparedStatement.

And BTW: How do you imagine we're supposed to know that your strings are part of an SQL statement?

is "SELECT * FROM Student WHERE StudentID = '" + stuID + "';"; equivalent to "SELECT * FROM Student WHERE StudentID = '" stuID "';";


No; because that 2nd statement won't compile.

Winston
 
kahkean chor
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so sad i dont get it....btw thanks for your reply
 
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