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 Post subject: Dialect using NHibernate - Works with everything but LINQ
PostPosted: Tue Apr 10, 2012 10:18 am 
Newbie

Joined: Tue Apr 10, 2012 10:15 am
Posts: 2
I solved a previous problem (how to add a hint in NHibernate) but partially. My code adds the with(nolock) to almost every query, all but LINQ. What is wrong with it ?

Code:
public class MsSQLWithNoLockDialect : NHibernate.Dialect.MsSql2005Dialect
{
    public MsSQLWithNoLockDialect() {
    }

    private bool NeedsLockHint(LockMode lockMode) {
        return true;
    }

    public override string AppendLockHint(LockMode lockMode, string tableName) {
        if (lockMode.GreaterThan(LockMode.Read)) {
            return tableName + " with (updlock, rowlock)";
        }

        return tableName + " with(nolock)";
    }

    private struct LockHintAppender
    {
        private readonly MsSQLWithNoLockDialect dialect;
        private readonly IDictionary<string, LockMode> aliasedLockModes;

        public LockHintAppender(MsSQLWithNoLockDialect dialect, IDictionary<string, LockMode> aliasedLockModes) {
            this.dialect = dialect;
            this.aliasedLockModes = aliasedLockModes;
        }

        public string ReplaceMatch(Match match) {
            string alias = match.Groups[1].Value;
            string lockHint = dialect.AppendLockHint(aliasedLockModes[alias], alias);
            return string.Concat(" ", lockHint, match.Groups[2].Value);
        }
    }

    public override SqlString ApplyLocksToSql(SqlString sql, IDictionary<string, LockMode> aliasedLockModes, IDictionary<string, string[]> keyColumnNames) {

        // Regex matching any alias out of those given. Aliases should contain
        // no dangerous characters (they are identifiers) so they are not escaped.
        string aliasesPattern = StringHelper.Join("|", aliasedLockModes.Keys);

        // Match < alias >, < alias,>, or < alias$>, the intent is to capture alias names
        // in various kinds of "FROM table1 alias1, table2 alias2".
        Regex matchRegex = new Regex(" (" + aliasesPattern + ")([, ]|$)");

        SqlStringBuilder result = new SqlStringBuilder();
        MatchEvaluator evaluator = new LockHintAppender(this, aliasedLockModes).ReplaceMatch;

        foreach (object part in sql.Parts) {
            if (part == Parameter.Placeholder) {
                result.Add((Parameter)part);
                continue;
            }

            result.Add(matchRegex.Replace((string)part, evaluator));
        }

        return result.ToSqlString();
    }

    public override JoinFragment CreateOuterJoinFragment() {
        return new ANSIWithNoLockJoinFragment();
    }
}


Its simple to understand, but I can't find a way to make it work !
I'm using linq-to-nhibernate !

Thanks !


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 Post subject: Re: Dialect using NHibernate - Works with everything but LINQ
PostPosted: Tue Apr 10, 2012 3:09 pm 
Newbie

Joined: Tue Apr 10, 2012 10:15 am
Posts: 2
any ideas ?

I know I have to extend some class, but I just don't know which !

Thanks !


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