Some changes to db

- Generic ScalarQuery is no longer used so removed
- Handle the case where the column length is > 0 but the number of rows is 0

src/db_column.c

@@ -154,6 +154,10 @@ struct column_data_t *columnFromResult(struct stored_conn_t *sconn, MYSQL_RES *r
   col->isBlob      = (field->flags & BLOB_FLAG) > 0;
   col->isTimestamp = (field->flags & TIMESTAMP_FLAG) > 0;
 
+  if (num_rows == 0) {
+    return col;
+  }
+
   col->data.vptr = malloc(col->type_bytes * num_rows);
   if (col->data.vptr == NULL) {
     fprintf(stderr, "[%d]malloc: (%d) %s\n", __LINE__, errno, strerror(errno));
@@ -163,7 +167,6 @@ struct column_data_t *columnFromResult(struct stored_conn_t *sconn, MYSQL_RES *r
   }
   memset(col->data.vptr, 0, col->type_bytes * num_rows);
 
-  col->data_sizes = 0;
   if (col->hasPointers) {
     col->data_sizes = (size_t *)malloc(sizeof(size_t) * num_rows);
     if (col->data_sizes == NULL) {
@@ -176,7 +179,6 @@ struct column_data_t *columnFromResult(struct stored_conn_t *sconn, MYSQL_RES *r
     memset(col->data_sizes, 0, sizeof(size_t) * num_rows);
   }
 
-  col->nulls = 0;
   if (col->isNullable) {
     col->nulls = malloc(num_rows / 8 + 1);
     if (col->nulls == NULL) {

src/db_query.c

@@ -20,83 +20,6 @@ uint64_t simpleQuery(struct stored_conn_t *sconn, const char *qry, size_t qry_le
   return mysql_insert_id(SQCONN(sconn));
 }
 
-uint64_t scalarQuery(struct stored_conn_t *sconn, const char *qry, size_t qry_len,
-                     char **res, size_t *res_len)
-{
-  my_ulonglong insertId;
-  my_ulonglong n_row, n_col;
-  MYSQL_RES *result;
-  MYSQL_ROW row;
-  unsigned long *lens;
-
-  insertId = simpleQuery(sconn, qry, qry_len);
-  if (insertId == (uint64_t)-1) {
-    return insertId;
-  }
-
-  if (mysql_field_count(SQCONN(sconn)) == 0) {
-    // insert/update query
-    // TODO: res = makeInt64() // lastInsertId
-    return insertId;
-  }
-
-
-  result = mysql_store_result(SQCONN(sconn));
-  if (result == NULL) {
-    fprintf(
-      stderr, "[%d]mysql_store_result: (%d) %s\n",
-      __LINE__, mysql_errno(SQCONN(sconn)), mysql_error(SQCONN(sconn))
-    );
-    return (uint64_t)-1;
-  }
-
-
-  n_row = mysql_num_rows(result);
-  if (n_row == 0) {
-    fprintf(stderr, "[%d]scalarQuery: Not enough rows in result\n", __LINE__);
-    return (uint64_t)-1;
-  }
-  if (n_row > 1) {
-    fprintf(
-      stderr, "[%d]scalarQuery: WARN: Too many rows in result, only returning first value\n",
-      __LINE__
-    );
-  }
-
-  n_col = mysql_num_fields(result);
-  if (n_col > 1) {
-    fprintf(
-      stderr, "[%d]scalarQuery: WARN: Too many columns in result, only returning first value\n",
-      __LINE__
-    );
-  }
-
-  row = mysql_fetch_row(result);
-  lens = mysql_fetch_lengths(result);
-  if (row == NULL) {
-    fprintf(stderr, "[%d]scalarQuery: Not enough rows in result\n", __LINE__);
-    return (uint64_t)-1;
-  }
-
-  if (*row == NULL) {
-    (*res_len) = 0;
-    (*res) = 0;
-  } else {
-    (*res_len) = *(lens + 0);
-    (*res) = malloc(*(lens + 0) * sizeof(char) + 1);
-    if ((*res) == 0) {
-      fprintf(stderr, "[%d]malloc: (%d) %s\n", __LINE__, errno, strerror(errno));
-      return (uint64_t)-1;
-    }
-    memcpy((*res), *(row + 0), *(lens + 0));
-    *((*res) + *(lens + 0)) = '\0';
-  }
-
-  mysql_free_result(result);
-
-  return insertId;
-}
-
 uint64_t tableQuery(struct stored_conn_t *sconn, const char *qry, size_t qry_len, int scalar_result,
                     struct column_data_t ***col_data_ptr, size_t *n_cols)
 {
@@ -115,7 +38,11 @@ uint64_t tableQuery(struct stored_conn_t *sconn, const char *qry, size_t qry_len
 
   *n_cols = mysql_field_count(SQCONN(sconn));
   if (scalar_result && (*n_cols) > 1) {
-    // TODO: throw warning due to column sizing issue
+    fprintf(
+      stderr,
+      "[%d]tableQuery: Scalar result expected, got %ul columns. Using first column value\n",
+      __LINE__, (unsigned int)*n_cols
+    );
     (*n_cols) = 1;
   }
   if (*n_cols == 0) {
@@ -135,11 +62,12 @@ uint64_t tableQuery(struct stored_conn_t *sconn, const char *qry, size_t qry_len
 
 
   col_data = (struct column_data_t **)malloc(sizeof(struct column_data_t *) * *n_cols);
-  if (result == NULL) {
+  if (col_data == NULL) {
     fprintf(stderr, "[%d]malloc: (%d) %s\n", __LINE__, errno, strerror(errno));
     mysql_free_result(result);
     return insertId;
   }
+  memset(col_data, 0, sizeof(struct column_data_t *) * *n_cols);
 
   n_rows = mysql_num_rows(result);
   if (scalar_result && n_rows > 1) {
@@ -215,15 +143,21 @@ int scalarInt(struct stored_conn_t *sconn, const char *qry, size_t qry_len, int
 {
   struct column_data_t **col_data;
   size_t n_cols;
+  uint64_t n_rows = tableQuery(sconn, qry, qry_len, 1, &col_data, &n_cols);
 
-  if (tableQuery(sconn, qry, qry_len, 1, &col_data, &n_cols) != (uint64_t)-1) {
+  if (n_rows == (uint64_t)-1) {
+    return default_value;
+  }
+
+  if (n_rows > 0) {
     if (!((*col_data)->isNullable && columnRowIsNull(*col_data, 0))) {
       default_value = *((*col_data)->data.ptr_int32);
     }
-    freeColumn(*col_data);
-    free(col_data);
   }
 
+  freeColumn(*col_data);
+  free(col_data);
+
   return default_value;
 }
 
@@ -232,15 +166,21 @@ unsigned int scalarUInt(struct stored_conn_t *sconn, const char *qry, size_t qry
 {
   struct column_data_t **col_data;
   size_t n_cols;
+  uint64_t n_rows = tableQuery(sconn, qry, qry_len, 1, &col_data, &n_cols);
 
-  if (tableQuery(sconn, qry, qry_len, 1, &col_data, &n_cols) != (uint64_t)-1) {
+  if (n_rows == (uint64_t)-1) {
+    return default_value;
+  }
+
+  if (n_rows > 0) {
     if (!((*col_data)->isNullable && columnRowIsNull(*col_data, 0))) {
       default_value = *((*col_data)->data.ptr_uint32);
     }
-    freeColumn(*col_data);
-    free(col_data);
   }
 
+  freeColumn(*col_data);
+  free(col_data);
+
   return default_value;
 }
 
@@ -249,15 +189,21 @@ double scalarReal(struct stored_conn_t *sconn, const char *qry, size_t qry_len,
 {
   struct column_data_t **col_data;
   size_t n_cols;
+  uint64_t n_rows = tableQuery(sconn, qry, qry_len, 1, &col_data, &n_cols);
 
-  if (tableQuery(sconn, qry, qry_len, 1, &col_data, &n_cols) != (uint64_t)-1) {
+  if (n_rows == (uint64_t)-1) {
+    return default_value;
+  }
+
+  if (n_rows > 0) {
     if (!((*col_data)->isNullable && columnRowIsNull(*col_data, 0))) {
       default_value = *((*col_data)->data.ptr_double);
     }
-    freeColumn(*col_data);
-    free(col_data);
   }
 
+  freeColumn(*col_data);
+  free(col_data);
+
   return default_value;
 }
 
@@ -265,15 +211,21 @@ char scalarChar(struct stored_conn_t *sconn, const char *qry, size_t qry_len, ch
 {
   struct column_data_t **col_data;
   size_t n_cols;
+  uint64_t n_rows = tableQuery(sconn, qry, qry_len, 1, &col_data, &n_cols);
 
-  if (tableQuery(sconn, qry, qry_len, 1, &col_data, &n_cols) != (uint64_t)-1) {
+  if (n_rows == (uint64_t)-1) {
+    return default_value;
+  }
+
+  if (n_rows > 0) {
     if (!((*col_data)->isNullable && columnRowIsNull(*col_data, 0))) {
       default_value = *((*col_data)->data.ptr_str)[0];
     }
-    freeColumn(*col_data);
-    free(col_data);
   }
 
+  freeColumn(*col_data);
+  free(col_data);
+
   return default_value;
 }
 
@@ -282,23 +234,27 @@ char *scalarString(struct stored_conn_t *sconn, const char *qry, size_t qry_len,
 {
   struct column_data_t **col_data;
   size_t n_cols;
-  char *retval;
+  char *retval = NULL;
+  uint64_t n_rows = tableQuery(sconn, qry, qry_len, 1, &col_data, &n_cols);
 
-  if (tableQuery(sconn, qry, qry_len, 1, &col_data, &n_cols) == (uint64_t)-1) {
+  if (n_rows == (uint64_t)-1) {
     return default_value;
   }
 
-  if ((*col_data)->isNullable && columnRowIsNull(*col_data, 0)) {
+  if (n_rows > 0) {
-    retval = NULL;
+    if (!((*col_data)->isNullable && columnRowIsNull(*col_data, 0))) {
-  } else {
+      retval = (char *)malloc((*col_data)->data_sizes[0] + 1);
-    retval = (char *)malloc((*col_data)->data_sizes[0] + 1);
+      if (retval == 0) {
-    if (retval == 0) {
+        fprintf(stderr, "[%d]malloc: (%d) %s\n", __LINE__, errno, strerror(errno));
-      fprintf(stderr, "[%d]malloc: (%d) %s\n", __LINE__, errno, strerror(errno));
+        freeColumn(*col_data);
-      return default_value;
+        free(col_data);
+        return NULL;
+      }
+      memcpy(retval, *((*col_data)->data.ptr_str), (*col_data)->data_sizes[0]);
+      retval[(*col_data)->data_sizes[0]] = '\0';
     }
-    memcpy(retval, *((*col_data)->data.ptr_str), (*col_data)->data_sizes[0]);
-    retval[(*col_data)->data_sizes[0]] = '\0';
   }
+
   freeColumn(*col_data);
   free(col_data);