// Convert an object into an SQL query value:
public virtual string Stringify()
{
// Format the value appropraitely.
if (Value is DateTime)
{
DateTime actualValue = ( DateTime )(Value);
return(String.Format("'{0}'", actualValue.ToString("yyyy-MM-dd HH:mm:ss")));
}
else if (Value is QueryElement)
{
QueryElement actualValue = ( QueryElement )(Value);
return(actualValue.Column);
}
else if (Value is DatabaseObject)
{
DatabaseObject actualValue = ( DatabaseObject )(Value);
actualValue.Validate();
return(String.Format("'{0}'", actualValue.Id));
}
else if (Value is DatabaseQuery)
{
DatabaseQuery actualValue = ( DatabaseQuery )(Value);
return(String.Format("({0})", actualValue.Select));
}
else
{
return(String.Format("'{0}'", Value));
}
}
// Function that executes a select statement.
protected int DoDelete(DatabaseQuery query)
{
if (!Valid)
{
return(0);
}
if (query.Comparator == null)
{
query.Comparator = Identifier;
}
Loaded = false;
MySqlCommand command = new MySqlCommand(query.Delete, Database.Connection);
return(command.ExecuteNonQuery());
}
// Function that executes a select statement.
protected MySqlDataReader DoLoad(DatabaseQuery query)
{
if (!Valid)
{
return(null);
}
if (query.Comparator == null)
{
query.Comparator = Identifier;
}
int columnCount = query.Count;
query.Add(Database.Tables.Generic.CREATED_ON_COLUMN_NAME);
query.Add(Database.Tables.Generic.LAST_UPDATED_COLUMN_NAME);
MySqlCommand command = new MySqlCommand(query.Select, Database.Connection);
MySqlDataReader reader = command.ExecuteReader();
if (reader.Read())
{
Loaded = true;
DateTime creationTime = reader.GetDateTime(columnCount++);
DateTime lastUpdateTime = reader.GetDateTime(columnCount);
if (CreatedOn < creationTime)
{
CreatedOn = creationTime;
}
if (LastSaved < lastUpdateTime)
{
LastSaved = lastUpdateTime;
}
}
else
{
Loaded = false;
}
return(reader);
}
// Function that executes an insert/update statement.
protected int DoSave(DatabaseQuery query)
{
bool exists = query.Exists;
if (Valid && exists)
{
// Use the default comparator if there is none existing.
if (query.Comparator == null)
{
query.Comparator = Identifier;
}
Loaded = true;
LastSaved = DateTime.Now;
query.Add(Database.Tables.Generic.LAST_UPDATED_COLUMN_NAME, LastSaved);
MySqlCommand command = new MySqlCommand(query.Update, Database.Connection);
return(command.ExecuteNonQuery());
}
else
{
// Add a new row and get it's ID.
CreatedOn = DateTime.Now;
LastSaved = DateTime.Now;
query.Add(Database.Tables.Generic.CREATED_ON_COLUMN_NAME, CreatedOn);
query.Add(Database.Tables.Generic.LAST_UPDATED_COLUMN_NAME, LastSaved);
MySqlCommand command = new MySqlCommand(query.Insert, Database.Connection);
command.ExecuteNonQuery();
if (!Valid)
{
id = ( int )(command.LastInsertedId);
Loaded = true;
}
return(1);
}
}
// Constructor for a sub-query
public QueryElement(DatabaseQuery subquery)
{
Column = null;
Value = subquery;
}