reading data from the database basics

src/main.c

@@ -1,4 +1,5 @@
 #include <duckdb.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 
@@ -9,20 +10,66 @@ int main(int argc, char** argv){
         printf("You need to specify a duckdb file path! Terminating!\n");
         exit(1);
     }
-    printf("First argument: %s", argv[1]);
+    printf("First argument: %s\n", argv[1]);
 
     duckdb_database db;
     if(duckdb_open(argv[1], &db) == DuckDBError){
-        printf("Error opening duckdb file, terminating!");
+        printf("Error opening duckdb file, terminating!\n");
         exit(2);
     }
 
     duckdb_connection conn;
     if(duckdb_connect(db, &conn) == DuckDBError){
-        printf("Error connecting to the duckdb database! Terminating!");
+        printf("Error connecting to the duckdb database! Terminating!\n");
         exit(3);
     }
 
 
+    //Test query
+    duckdb_result result;
+    duckdb_query(conn, "SELECT * from \"Engine RPM\";\n", &result);
+    int32_t iterations = 0;
+    int32_t number_of_data_points = 0;
+
+    while(true){
+        iterations++;
+
+        duckdb_data_chunk data_chunk = duckdb_fetch_chunk(result);
+        
+        if(!data_chunk){
+            break;
+        }
+
+        idx_t row_count = duckdb_data_chunk_get_size(data_chunk); //number of rows from the data chunk
+
+        //first column
+        duckdb_vector col1 = duckdb_data_chunk_get_vector(data_chunk, 0);
+        int32_t *col1_data = (int32_t *) duckdb_vector_get_data(col1);
+        uint64_t *col1_validity = duckdb_vector_get_validity(col1);
+
+        for (idx_t row = 0; row < row_count; row++) {
+            number_of_data_points++;
+            if(duckdb_validity_row_is_valid(col1_validity, row)){
+                printf("%d, ", col1_data[row]);
+            }else{
+                printf("NULL");
+            }
+        }
+
+        duckdb_destroy_data_chunk(&data_chunk);
+    }
+
+    printf("\nNumber of iterations: %d, number of data points: %d\n", iterations, number_of_data_points);
+
+    printf("Shutting down HardCompound!\n");
+
+    printf("Destroying result!\n");
+    duckdb_destroy_result(&result);
+
+    printf("Closing database and any connection.\n");
+    duckdb_disconnect(&conn);
+    duckdb_close(&db);
+
+
     return 0;
 }