Database.Exists is not optimal about npoco

[zii-dmg]

Attempt to use GetExistsSql + custom WHERE overload + expression WHERE overload. Tested only with non-composite primary key on MySql.

public bool ExistsById<T>(object primaryKey) // renamed old Exists(object primaryKey) method
{
    var index = 0;
    var pd = PocoData.ForType(typeof(T), PocoDataFactory);
    var tableName = DatabaseType.EscapeTableName(pd.TableInfo.TableName);
    var pkValues = GetPrimaryKeyValues(pd.TableInfo.PrimaryKey, primaryKey);
    var pkSql = BuildPrimaryKeySql(pkValues, ref index);
    var sql = string.Format(_dbType.GetExistsSql(), tableName, pkSql);
    var args = pkValues.Select(x => x.Value).ToArray();
    return ExecuteScalar<int>(sql, args) != 0;
}

public bool Exists<T>(Sql sql)
{
    return Exists<T>(sql.SQL, sql.Arguments);
}

public bool Exists<T>(string sql, params object[] args)
{
    var pd = PocoData.ForType(typeof(T), PocoDataFactory);
    var tableName = DatabaseType.EscapeTableName(pd.TableInfo.TableName);

    if (sql.StartsWith("WHERE", StringComparison.InvariantCultureIgnoreCase))
    {
        sql = sql.Substring(5);
    }

    var fullSql = string.Format(_dbType.GetExistsSql(), tableName, sql);
    return ExecuteScalar<int>(fullSql, args) != 0;
}

public bool Exists<T>(Expression<Func<T, bool>> expression)
{
    var ev = _dbType.ExpressionVisitor<T>(this);
    var sql = ev.Where(expression).Context.ToWhereStatement();
    var args = ev.Context.Params.ToArray();
    return Exists<T>(sql, args);
}

[mabakay]

Is it and when if is planed to commit this code to branch?

[schotime]

The Exists has been changed to use the Count(*) sql, and the expression based exists is now available via the Query().Any() method.
I'm still thinking about the middle two. Might not be as necessary if you have the linq way.
Now available on Nuget 2.4.60+

[zii-dmg]

As code is now using GetExistsSql I think I can close this.