public override string Translate(SqlCompilerContext context, SqlUnary node, NodeSection section)
{
//substitute UNIQUE predicate with a more complex EXISTS predicate,
//because UNIQUE is not supported
if (node.NodeType == SqlNodeType.Unique)
{
if (node.Operand is SqlSubQuery origSubselect)
{
var origQuery = SqlDml.QueryRef(origSubselect.Query);
var existsOp = SqlDml.Select(origQuery);
existsOp.Columns.Add(1);
existsOp.Where = true;
foreach (SqlColumn col in origQuery.Columns)
{
existsOp.Where = existsOp.Where && SqlDml.IsNotNull(col);
existsOp.GroupBy.Add(col);
}
existsOp.Having = SqlDml.Count(SqlDml.Asterisk) > 1;
existsOp.Limit = 1;
node.ReplaceWith(SqlDml.Not(SqlDml.Exists(existsOp)));
}
}
return(base.Translate(context, node, section));
}
public void SqlUnaryReplacingTest()
{
SqlUnary u = -SqlDml.Literal(1);
SqlUnary uReplacing = ~SqlDml.Literal(2);
u.ReplaceWith(uReplacing);
bool passed = false;
try {
u.ReplaceWith(1);
}
catch {
passed = true;
}
Assert.IsTrue(passed);
Assert.AreNotEqual(u, uReplacing);
Assert.AreEqual(u.NodeType, uReplacing.NodeType);
Assert.AreEqual(u.Operand, uReplacing.Operand);
}
