public virtual SqlFragment BuildSqlForSqlFunctionExpression(SqlFunctionExpression expr)
{
SqlTemplate template = SqlDialect.GetSqlFunctionTemplate(expr);
if (template != null)
{
var args = expr.GetOperands();
var sqlArgs = args.Select(a => BuildLinqExpressionSql(a)).ToArray();
return(template.Format(sqlArgs));
}
return(BuildSqlForSqlFunctionExpressionNoTemplate(expr));
}//class
public virtual SqlFragment BuildAggregateSql(AggregateExpression expr)
{
if (expr.AggregateType == AggregateType.Count && expr.Operands.Count == 0)
{
return(this.SqlDialect.SqlCountStar);
}
SqlTemplate template = SqlDialect.GetAggregateTemplate(expr);
if (template != null)
{
var args = expr.GetOperands();
var sqlArgs = args.Select(a => BuildLinqExpressionSql(a)).ToArray();
return(template.Format(sqlArgs));
}
Util.Throw("Unsupported Aggregate type: {0}, expr: {1} ", expr.AggregateType, expr);
return(null);
}
}//method
public virtual SqlFragment BuildSqlForSqlExpression(SqlExpression expr)
{
switch (expr.SqlNodeType)
{
case SqlExpressionType.Alias:
var aliasExpr = (AliasedExpression)expr;
return(BuildLinqExpressionSql(aliasExpr.Expression)); //Alias will be added later
case SqlExpressionType.SqlFunction:
return(BuildSqlForSqlFunctionExpression((SqlFunctionExpression)expr));
case SqlExpressionType.Column:
var colExpr = (ColumnExpression)expr;
return(GetColumnRefSql(colExpr, forOutput: false));
case SqlExpressionType.SubSelect:
var subs = (SubSelectExpression)expr;
var subSelect = BuildSqlForSqlExpression(subs.Select);
return(CompositeSqlFragment.Parenthesize(subSelect));
case SqlExpressionType.Table:
var te = (TableExpression)expr;
return(te.TableInfo.SqlFullName);
case SqlExpressionType.TableFilter:
var tfe = (TableFilterExpression)expr;
var argParts = BuildSqls(tfe.Columns);
var sqlTempl = new SqlTemplate(tfe.Filter.EntityFilter.Template.StandardForm);
var part = sqlTempl.Format(argParts);
return(part);
case SqlExpressionType.ExternalValue:
var extValue = (ExternalValueExpression)expr;
var ph = CreateSqlPlaceHolder(extValue);
// it is already added to placeholders list
return(ph);
case SqlExpressionType.Group:
var ge = (GroupExpression)expr;
return(BuildLinqExpressionSql(ge.GroupedExpression));
case SqlExpressionType.OrderBy:
return(BuildOrderByMember((OrderByExpression)expr));
case SqlExpressionType.Aggregate:
return(BuildAggregateSql((AggregateExpression)expr));
case SqlExpressionType.Select:
var selectSql = BuildSelectSql((SelectExpression)expr);
return(CompositeSqlFragment.Parenthesize(selectSql));
case SqlExpressionType.DerivedTable:
// Looks like we never come here
//!!! investigate this
//TODO: investigate DerivedTable SQL
return(SqlTerms.Star);
default:
Util.Throw("SqlExpression->SQL not implemented, SqlNodeType: {0}", expr.SqlNodeType);
return(null); //never happens
}//switch
}//method