Check SQL query passed to execute

When `extra_check` feature is activated:
Fail when query has a column count > 0
Or when query is readonly.

src/statement.rs

@@ -511,6 +511,7 @@ impl Statement<'_> {
     }
 
     fn execute_with_bound_parameters(&mut self) -> Result<usize> {
+        self.check_update()?;
         let r = self.stmt.step();
         self.stmt.reset();
         match r {
@@ -547,6 +548,30 @@ impl Statement<'_> {
         Ok(())
     }
 
+    #[cfg(all(feature = "bundled", feature = "extra_check"))]
+    #[inline]
+    fn check_update(&self) -> Result<()> {
+        if self.column_count() > 0 || self.stmt.readonly() {
+            return Err(Error::ExecuteReturnedResults);
+        }
+        Ok(())
+    }
+
+    #[cfg(all(not(feature = "bundled"), feature = "extra_check"))]
+    #[inline]
+    fn check_update(&self) -> Result<()> {
+        if self.column_count() > 0 {
+            return Err(Error::ExecuteReturnedResults);
+        }
+        Ok(())
+    }
+
+    #[cfg(not(feature = "extra_check"))]
+    #[inline]
+    fn check_update(&self) -> Result<()> {
+        Ok(())
+    }
+
     /// Returns a string containing the SQL text of prepared statement with
     /// bound parameters expanded.
     #[cfg(feature = "bundled")]