public override void Visit(WSelectQueryBlock node)
{
if (node.SelectElements == null || node.SelectElements.Count < 2)
{
throw new GraphViewException("Numbers of select elements mismatch.");
}
var sourceTableScalar = node.SelectElements[0] as WSelectScalarExpression;
if (sourceTableScalar == null)
throw new GraphViewException("Source node id should be a scalar expression.");
var sourceTableColumn = sourceTableScalar.SelectExpr as WColumnReferenceExpression;
if (sourceTableColumn == null)
throw new GraphViewException("Source node id column should be a column reference expression.");
var sourceTableName = sourceTableColumn.MultiPartIdentifier.Identifiers.Last().Value;
var sourceNodeIdExpr = new WColumnReferenceExpression();
foreach (var identifier in sourceTableColumn.MultiPartIdentifier.Identifiers)
sourceNodeIdExpr.Add(identifier);
sourceNodeIdExpr.AddIdentifier("GlobalNodeId");
if (node.SelectElements.Count < 2)
throw new GraphViewException("Source and Sink tables should be specified in select elements.");
if (node.GroupByClause != null)
{
throw new GraphViewException("GROUP BY clause is not allowed in INSERT EDGE statement.");
}
var collectVarVisitor = new CollectVariableVisitor();
var context = collectVarVisitor.Invoke(node);
WColumnReferenceExpression sinkNodeIdExpr = null;
for (var index = 1; index < node.SelectElements.Count; ++index)
{
var element = node.SelectElements[index] as WSelectScalarExpression;
if (element == null)
throw new GraphViewException("Edge property should be a scalar expression.");
//sink table
if (index == 1)
{
var sinkTableColumn = element.SelectExpr as WColumnReferenceExpression;
if (sinkTableColumn == null)
throw new GraphViewException("Sink node id column should be a column reference expression.");
var sinkTableName = sinkTableColumn.MultiPartIdentifier.Identifiers.Last().Value;
_sinkTable = context[sinkTableName];
sinkNodeIdExpr = new WColumnReferenceExpression();
foreach (var identifier in sinkTableColumn.MultiPartIdentifier.Identifiers)
sinkNodeIdExpr.Add(identifier);
sinkNodeIdExpr.AddIdentifier("GlobalNodeId");
}
else
{
_edgeProperties.Add(element.SelectExpr);
}
}
var sourceTable = context[sourceTableName] as WNamedTableReference;
if (sourceTable == null)
{
throw new GraphViewException("Source table of INSERT EDGE statement should be a named table reference.");
}
var sourceNodeId = new WSelectScalarExpression
{
SelectExpr = sourceNodeIdExpr,
ColumnName = "src",
};
var sinkNodeId = new WSelectScalarExpression
{
SelectExpr = sinkNodeIdExpr,
ColumnName = "sink"
};
var elements = new List<WSelectElement>
{
sourceNodeId,
sinkNodeId
};
var result = new WCommonTableExpression
{
ExpressionName = new Identifier {Value = _tempTableName},
QueryExpression = new WSelectQueryBlock
{
FromClause = node.FromClause,
WhereClause = new WWhereClause
{
SearchCondition = node.WhereClause.SearchCondition
},
HavingClause = node.HavingClause,
OrderByClause = node.OrderByClause,
TopRowFilter = node.TopRowFilter,
UniqueRowFilter = node.UniqueRowFilter,
SelectElements = elements,
MatchClause = node.MatchClause
}
};
_result = result;
}
public virtual void Visit(WCommonTableExpression node)
{
node.AcceptChildren(this);
}
