/// <summary>
/// Performs a lookup for the PK value of a given entity by querying the table using a specific field mapping
/// </summary>
/// <param name="connection">
/// The database connection to the microsoft access database file.
/// </param>
/// <param name="description">
/// The source description including the table name to be used.
/// </param>
/// <param name="fieldMapping">
/// The field mapping.
/// </param>
/// <param name="contact">
/// The contact for find.
/// </param>
/// <returns>
/// the primary key value of the entity or null if not in database
/// </returns>
private static string GetPrimaryKeyForEntity(
OleDbConnection connection, SourceDescription description, ColumnDefinition fieldMapping, StdContact contact)
{
var value = FormatForDatabase(Tools.GetPropertyValue(contact, fieldMapping.Selector), fieldMapping);
if (value == SqlDatabaseNullString)
{
return(null);
}
using (var cmd = connection.CreateCommand())
{
var text = string.Format(
CultureInfo.InvariantCulture,
SqlStatementSelectPk,
description.GetPrimaryKeyName(),
description.MainTable,
fieldMapping.Title,
FormatForDatabase(Tools.GetPropertyValue(contact, fieldMapping.Selector), fieldMapping));
cmd.CommandText = text;
var result = cmd.ExecuteScalar();
return((result ?? string.Empty).ToString());
}
}
