private static ExtractKeysResult ExtractKeys(ExprMerge merge, IExprAlias sourceAlias)
{
IExprAlias targetAlias = merge.TargetTable.Alias?.Alias ?? throw new SqExpressException("Target table should have an alias");
var accSource = new List <ExprColumnName>();
var accTarget = new List <ExprColumnName>();
var eqs = merge.On.SyntaxTree().DescendantsAndSelf().OfType <ExprBooleanEq>();
foreach (var exprBooleanEq in eqs)
{
if (exprBooleanEq.Left is ExprColumn left &&
exprBooleanEq.Right is ExprColumn right &&
left.Source is ExprTableAlias ta &&
right.Source is ExprTableAlias sa)
{
if (sa.Alias.Equals(sourceAlias) && ta.Alias.Equals(targetAlias))
{
accTarget.Add(left.ColumnName);
accSource.Add(right.ColumnName);
}
else if (ta.Alias.Equals(sourceAlias) && sa.Alias.Equals(targetAlias))
{
accTarget.Add(right.ColumnName);
accSource.Add(left.ColumnName);
}
}
}
return(new ExtractKeysResult(accTarget, accSource));
}
public static ExprTableAlias WithAlias(this ExprTableAlias original, IExprAlias newAlias) => new ExprTableAlias(alias: newAlias);
internal MergeDataBuilder(TTable table, IEnumerable <TItem> data, IExprAlias sourceTableAlias)
{
this._table = table;
this._data = data;
this._sourceTableAlias = new ExprTableAlias(sourceTableAlias);
}
public ExprTableAlias(IExprAlias alias)
{
this.Alias = alias;
}
public static Alias From(IExprAlias exprAlias) => new Alias(false, null, exprAlias);
