Question

I have a SQLite database with some fields of type double and I have to extract this value and put them in an instance variable, but I get this error

  Assigning to 'double *' from incompatible type 'double'

this is the code:

DatabaseTable.h

   @interface DatabaseTable : NSObject {
sqlite3 * database;

   }

   //........
   @property (nonatomic, assign)double *latitude; //latitude is a field of type double
   @property (nonatomic, assign)double *longitude; //longitude is a field of a type double

   @end

DatabaseTable.m

   //.....
    while (sqlite3_step(statement) == SQLITE_ROW) {

       DatabaseTable * rowTable =[[ChinaDatabaseTable alloc]init];
           //.......

           rowTable.latitude =sqlite3_column_double(statement, 15); //here the error
           rowTable.longitude =sqlite3_column_double(statement, 16);//here the error

           //.....
     }

What can I do?

Answer 1

You don’t need to put a * before the primitive types like int, float, bool etc.

So change the code like:

   @property (nonatomic, assign)double latitude; //latitude is a field of type double
   @property (nonatomic, assign)double longitude; //longitude is a field of a type double

If you need to create a pointer variable then your code is ok.

But you can’t assign values directly to a pointer value for the primitive types.

If you need to assign the address value, you need to do like:

double temp = sqlite3_column_double(statement, 15);
rowTable.latitude = &temp;