The mi_column_default_string() function

Syntax

mi_integer mi_column_default_string(row_desc, column_id, 
                                    default_val)
   MI_ROW_DESC *row_desc;
   mi_integer  column_id;
   mi_string   **default_val;

row_desc

A pointer to the row descriptor for the row that contains the column.

column_id

Indicates the column identifier, which specifies the position of the column in the specified row descriptor. Column numbering follows C array-indexing conventions: the first column in the row descriptor is at position zero.

default_val

A pointer to an mi_string buffer that contains the column default value. The mi_column_default_string() function allocates the mi_string buffer. The default_val parameter is passed by reference.

Usage

The mi_column_default_string() function returns the default value that is defined for the column by the DEFAULT clause of the CREATE TABLE or ALTER TABLE statements. The mi_column_default_string() function returns the default value for the column in string representation.

For example, you can create a table with two columns that have default values:

CREATE TABLE tab(col1 int DEFAULT 10, col2 varchar(12) DEFAULT 'permanent');

The mi_column_default_string() function returns a string with the values 10 and ’permanent’.

Return values

0

The specified column is not defined with a default value.

1 and the contents of the mi_string buffer

The specified column contains a default value. If the value of the mi_string structure is NULL, the default value of the column is NULL.

MI_ERROR

The function was not successful.