private List <IPlanStep> GetDeleteSteps(DeleteStatement statement)
{
var result = new List <IPlanStep>();
var step = new DeleteStep();
step.DatabaseName = statement.DatabaseName;
step.TableName = statement.Tables.First();
if (statement.HasWhereClause)
{
// need to delete only the rows in the where clause
step.InputStep = QueryPlanGeneratorUtility.GetMaxStep(_plan.Steps);
step.Level = step.InputStep.Level++;
var rows = step.InputStep.GetResult(_process, statement.DatabaseName).Rows;
step.DeletedRows = rows;
}
else
{
// delete everything
step.ShouldDeleteAllRows = true;
}
result.Add(step);
return(result);
}
public QueryPlan GeneratePlan(UpdateStatement statement)
{
var result = new QueryPlan();
statement.ParseElements();
// TO DO: We need to extract out from the Select Plan Generator
// a generic WhereClausePlanGenerator because the behavior should be the same, i.e.
// generate the plan steps to find the rows that apply to a WHERE clause
// and then either return those rows or take an action on them (DELETE, or UPDATE)
result.Steps.AddRange(GetWhereClauseSteps(statement));
_level = QueryPlanGeneratorUtility.GetMaxLevel(result.Steps);
result.Steps.AddRange(GetUpdateSteps(statement, result.Steps));
result.OriginalStatement = statement;
return(result);
}
// TO DO: We need to figure out how to input the rows we wish to affect
private List <IPlanStep> GetUpdateSteps(UpdateStatement statement, List <IPlanStep> existingSteps)
{
var result = new List <IPlanStep>();
foreach (var element in statement.Elements)
{
var step = new UpdateStep();
if (statement.HasWhereClause)
{
step.InputStep = QueryPlanGeneratorUtility.GetMaxStep(existingSteps);
}
step.TableName = element.TableName;
step.DatabaseName = element.DatabaseName;
step.ColumnName = element.ColumnName;
step.Value = element.Value;
_level++;
step.Level = _level;
result.Add(step);
}
return(result);
}
