DIL column types and query result types

/* Generic column types. */
typedef enum DB_Type_enum
{ 
  DB_CHAR, DB_INT1, DB_INT2, DB_INT4, DB_INT8, 
  DB_FLOAT, DB_DOUBLE, 
  DB_STRING, DB_VARCHAR
} DB_Type_t; 


/* Binary query result column. */
typedef struct DB_Column_struct
{
  char *column_name;     /* Name of the column. */
  DB_Type_t type;        /* The data type. */
  unsigned int num_rows; /* Number of rows in the column.  */
  unsigned int size;     /* Size of data type. */
  char *data;            /* Array of type "type" holding the column data. 
                            The total length of *column_data is num_rows*size. 
                         */
  signed short *is_null;  /* An array of flags indicating if the field
                             contained a NULL value. */
} DB_Column_t;

/* Binary query result table. */
typedef struct DB_Binary_Result_struct
{
  unsigned int num_rows;  /* Number of rows in result. */
  unsigned int num_cols;  /* Number of columns in result. */
  DB_Column_t *column;
} DB_Binary_Result_t;


/* Text query result table. */
typedef struct DB_Text_Result_struct
{
  unsigned int num_rows;
  unsigned int num_cols;
  char **column_name;     /* Name of the column. */
  int *column_width;      /* Max width of the column. */
  char *buffer;           /* buffers holding the results. On buffer per row. */
  char ***field;          /* field[i][j] is a string contained in the i'th row 
                             and j'th column of the result. */ 
} DB_Text_Result_t;