About android SQLite rawQuery return value in question

When we encounter a problem, seeking to explain
brightest Great GodI now want to query about whether the presence of a row of data, if there is data on the update, otherwise insert a row

I was doing:
Cursor cursor = cdb.rawQuery ("SELECT * FROM" + current_table_name + "WHERE begin_class = 10");

If the table does not exist begin_class = row 10 it?? How the cursor from function to return there to judge them?? Because I found that even non-existent, return the cursor is not null. Document seemingly did not explain this problem? Sincerely seeking answers .

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Seeking to explain ah ... stuck in here
Reply:
No value it wants
Reply:

reference to the second floor othereyeopen reply:

not value it wants

I tried to determine cursor == null and cursor.isNull (0) will not ah .. but the latter also being given
Ask, what are other ways to solve??
Reply:
cursor == null | | cursor.getCount () <= 0
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references, 4th Floor lizhengjun2010 reply:

cursor == null | | cursor.getCount () <= 0

In this case still has true ah ... you told me this or condition only cursor == null is the same, right?
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while (cursor! = null && cursor.getCount ()> 0)
This has been true?????
Reply:

reference to the 6th floor lizhengjun2010 reply:

while (! cursor = null && cursor.getCount ()> 0)
This has been true?????

According to your changes, my code is:

 
cursor = cdb.rawQuery ("?? WHERE begin_class = AND lasting =" "SELECT * FROM" + current_table_name +, new String [] {"" + beginClass, "" + lasting}); 
if (cursor == null | | cursor.getCount () <= 0) {
cdb.update (current_table_name, values, "begin_class =" + beginClass, null); 
} 
else {
cdb.insert (current_table_name, null, values); 
} 

In this case, I found that regardless of whether the result is an empty look, can only perform update statement, the if-else statements exchanged over the two, then it can only perform insert, ie cursor == null | | cursor.getCount () <= 0 results returned has been true
Reply:
cursor.getCount ()
Before and after the update, the print out to see ... whether this change ..
Reply:
I encountered a similar problem with you, now resolved, Reference: http://blog.sina.com.cn/s/blog_4ea108170100rp4y.html
Reply:
if (cursor! = null && cursor.getCount ()> = 0)
{
/ / Operation
}