/// <summary>
/// Reads the current node in the abstract syntax tree.
/// </summary>
/// <param name="node">The current node in the abstract syntax tree.</param>
/// <param name="plan">The <see cref="QueryExecutionPlan"/> currently being built.</param>
private void ReadClause(ParseTreeNode node, QueryExecutionPlan plan)
{
foreach (var builder in this.builders)
{
builder.BuildOperation(scope, node, plan);
}
}
/// <summary>
/// Reads the current node in the abstract syntax tree.
/// </summary>
/// <param name="node">The current node in the abstract syntax tree.</param>
/// <param name="plan">The <see cref="QueryExecutionPlan"/> currently being built.</param>
private void ReadClause(ParseTreeNode node, QueryExecutionPlan plan)
{
foreach (var builder in this.builders)
{
if (scope.Count >= 2 && scope.ElementAt(scope.Count - 2) == builder.OperationName)
{
builder.BuildOperation(scope, node, plan);
}
}
}
/// <summary>
/// Builds the <see cref="QueryExecutionPlan"/> by parsing the abstract syntax tree generated by the <see cref="DqlQueryGrammar"/>.
/// </summary>
/// <param name="node">Current node in the abstract syntax tree.</param>
/// <param name="plan">The <see cref="QueryExecutionPlan"/> currently being built.</param>
/// <returns><see cref="QueryExecutionPlan"/> that is prepared for execution against the database.</returns>
public QueryExecutionPlan BuildQueryExecutionPlan(ParseTreeNode node, QueryExecutionPlan plan)
{
scope.Push(node.Term.Name);
this.ReadClause(node, plan);
foreach (ParseTreeNode child in node.ChildNodes)
{
this.BuildQueryExecutionPlan(child, plan);
}
scope.Pop();
return plan;
}
/// <summary>
/// Builds the <see cref="QueryExecutionPlan"/> by parsing the abstract syntax tree generated by the <see cref="DqlQueryGrammar"/>.
/// </summary>
/// <param name="node">Current node in the abstract syntax tree.</param>
/// <param name="plan">The <see cref="QueryExecutionPlan"/> currently being built.</param>
/// <returns><see cref="QueryExecutionPlan"/> that is prepared for execution against the database.</returns>
public QueryExecutionPlan BuildQueryExecutionPlan(ParseTreeNode node, QueryExecutionPlan plan)
{
scope.Push(node.Term.Name);
this.ReadClause(node, plan);
foreach (ParseTreeNode child in node.ChildNodes)
{
this.BuildQueryExecutionPlan(child, plan);
}
scope.Pop();
return(plan);
}
/// <summary>
/// Build the current operation in the <see cref="QueryExecutionPlan"/> by reading the abstract syntax tree.
/// </summary>
/// <param name="scope">Scope of the current <see cref="ParseTreeNode"/>.</param>
/// <param name="node">Current <see cref="ParseTreeNode"/> in the abstract syntax tree.</param>
/// <param name="plan">The current <see cref="QueryExecutionPlan"/> being built.</param>
public void BuildOperation(Stack<string> scope, ParseTreeNode node, QueryExecutionPlan plan)
{
if (node.Term.Name == this.OperationName)
{
// Select clause
plan.Operations.Add(new SelectOperation());
}
var operation = (SelectOperation)plan.Current;
if (scope.Contains("selList") && node.Term.Name == "id_simple")
{
// Select column list
operation.ColumnNames.Add(node.Token.ValueString);
}
else if (scope.Contains("selList") && node.Term.Name == "*")
{
// Select column list
operation.ColumnNames.Add(node.Token.ValueString);
}
else if (scope.Contains("fromClauseOpt") && node.Term.Name == "id_simple")
{
// From clause
operation.TableName = node.Token.ValueString;
}
else if (scope.Contains("whereClauseOpt") && node.Term.Name == "binExpr")
{
// Where clause
if (node.ChildNodes[0].Term.Name == "binExpr")
{
// Handle multiple where clauses.
foreach (var child in node.ChildNodes)
{
if (child.Term.Name == "binExpr")
{
var column = child.ChildNodes[0].ChildNodes[0].Token.ValueString;
var val = child.ChildNodes[2].Token.ValueString;
operation.WhereClauses.Add(column, val);
}
}
}
else if (node.Term.Name == "binExpr" && operation.WhereClauses.Count == 0)
{
// Handle a single where clause.
var column = node.ChildNodes[0].ChildNodes[0].Token.ValueString;
var val = node.ChildNodes[2].Token.ValueString;
operation.WhereClauses.Add(column, val);
}
}
}
/// <summary>
/// Build the current operation in the <see cref="QueryExecutionPlan"/> by reading the abstract syntax tree.
/// </summary>
/// <param name="scope">Scope of the current <see cref="ParseTreeNode"/>.</param>
/// <param name="node">Current <see cref="ParseTreeNode"/> in the abstract syntax tree.</param>
/// <param name="plan">The current <see cref="QueryExecutionPlan"/> being built.</param>
public void BuildOperation(Stack<string> scope, ParseTreeNode node, QueryExecutionPlan plan)
{
UpdateOperation operation;
if (node.Term.Name == this.OperationName)
{
// Update statement
operation = new UpdateOperation();
operation.TableName = node.ChildNodes[1].ChildNodes[0].Token.ValueString;
plan.Operations.Add(operation);
}
operation = (UpdateOperation) plan.Current;
if (node.Term.Name == "assignment")
{
operation.Assignments.Add(node.ChildNodes[0].ChildNodes[0].Token.ValueString, node.ChildNodes[2].Token.ValueString);
}
else if (scope.Contains("whereClauseOpt") && node.Term.Name == "binExpr")
{
// Where clause
if (node.ChildNodes[0].Term.Name == "binExpr")
{
// Handle multiple where clauses.
foreach (var child in node.ChildNodes)
{
if (child.Term.Name == "binExpr")
{
var column = child.ChildNodes[0].ChildNodes[0].Token.ValueString;
var val = child.ChildNodes[2].Token.ValueString;
operation.WhereClauses.Add(column, val);
}
}
}
else if (node.Term.Name == "binExpr" && operation.WhereClauses.Count == 0)
{
// Handle a single where clause.
var column = node.ChildNodes[0].ChildNodes[0].Token.ValueString;
var val = node.ChildNodes[2].Token.ValueString;
operation.WhereClauses.Add(column, val);
}
}
}
