/// <summary>
/// Creates a new SET expression.
/// </summary>
/// <param name="expressionType">Expression type.</param>
/// <param name="column">Column which is to be changed.</param>
/// <param name="sourceColumns">Columns required by the expression to compute the new value.
/// Required to properly render the FROM clause when columns from other tables are used.
/// <b>Null</b> if the expression doesn't use any columns.</param>
/// <param name="item">SQL item that computes/contains the new value.</param>
/// <param name="itemType">Item type.</param>
internal UpdateExpression(UpdateExpressionType expressionType, IDbColumn column, DbColumnCollection sourceColumns, object item, SqlItemType itemType)
: this(item, itemType)
{
this.ExpressionType = expressionType;
this.column = column;
if (sourceColumns == null || sourceColumns.Count == 0)
this.sourceColumns = new IDbColumn[0];
else
this.sourceColumns = sourceColumns.ToArray();
}
/// <summary>
/// Creates a new predicate item.
/// </summary>
/// <param name="item">Item.</param>
/// <param name="itemType">Item type.</param>
internal PredicateItem(object item, SqlItemType itemType)
{
switch (itemType)
{
case SqlItemType.Column:
InitColumn((IDbColumn)item);
break;
case SqlItemType.FreeText:
InitFreeText((string)item);
break;
case SqlItemType.Function:
InitFunction((Function)item);
break;
case SqlItemType.Parameter:
DbParameter par = (DbParameter)item;
InitParameter(par.Value, par.DbType, par.Size, par.ParameterName);
break;
case SqlItemType.SubQuery:
InitQuery((SelectStatement)item);
break;
}
}
private UpdateExpression(object item, SqlItemType itemType)
: this()
{
this.Item = item;
this.ItemType = itemType;
}
private void InitColumn(IDbColumn column)
{
this.item = column;
this.itemType = SqlItemType.Column;
this.dataType = column.DataType;
this.dbType = column.DbType;
this.alias = column.Alias;
}
private void InitQuery(SelectStatement query)
{
this.item = query;
this.itemType = SqlItemType.SubQuery;
SqlItemUtil.TryDetermineSubQueryDataType(query, out this.dataType, out this.dbType);
this.alias = query.Alias;
}
private void InitParameter(object parameterValue, DbType parameterType, int size, string parameterNamePrefix)
{
// Unique parameter ID is automatically appended to parameter name during the rendering phase.
// Eg: 'parameter_15'. This is a safety precaution. It is possible that there are more
// parameters with the same name.
DbParameter dbpar = new DbParameter();
dbpar.ParameterName = SqlItemUtil.CleanParameterName(parameterNamePrefix);
dbpar.Direction = ParameterDirection.Input;
dbpar.DbType = parameterType;
dbpar.Value = parameterValue;
if (size > 0)
dbpar.Size = size;
this.item = dbpar;
this.itemType = SqlItemType.Parameter;
this.dataType = DBTypeUtil.NetTypeFrom(parameterType);
this.dbType = parameterType;
}
private void InitFunction(Function function)
{
this.item = function;
this.itemType = SqlItemType.Function;
this.dataType = function.DataType;
this.dbType = function.DbType;
this.alias = function.Alias;
}
private void InitFreeText(string freeText)
{
this.item = freeText;
this.itemType = SqlItemType.FreeText;
}
