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DataReader questions Messages   Related Types This message was discovered on ASPFriends.com 'ngfx-sqlclient' list. Responses highlighted in red are from those people who are likely to be able to contribute good, authoratitive information to this discussion. They include Microsoft employees, MVP's and others who IMHO contribute well to these kinds of discussions. Bill Bassler -- Moved from [aspngfreeforall] to [ngfx-sqlclient] by Marcie Jones <Click here to reveal e-mail address> -- 1. What method to use when want to specify a fieldname instead of an ordinal? 2. What are e.g. GetSqlInt32, GetSqlChar methods for? Should I use the types fro efficiency's sake when using SQL Server? * code snippets appreciated Reply to this message...        Tim Curtin reader("fieldname") [Original message clipped] _________________________________________________________________ Join the world’s largest e-mail service with MSN Hotmail. http://www.hotmail.com Reply to this message...        Graham Dobson . It is recommended that you use the typed accessor methods of the DataReader when you know the specific type of the value being returned. Typed accessor methods result in better performance by returning a value as a specific .NET Framework type, eliminating the need for additional type conversion. The SqlDataReader exposes SQL Server–specific typed accessor methods if a .NET Framework type does not meet the needs of the application. SQL Server–specific typed accessor methods return objects of System.Data.SqlType. Not sure exactly what you mean by specifying field names...All this can be read in the SDK under "Mapping .NET Data Provider Data Types to .NET Framework Data Types".... Graham -----Original Message----- From: Bill Bassler [mailto:Click here to reveal e-mail address] Sent: Tuesday, July 09, 2002 12:59 PM To: ngfx-sqlclient Subject: [ngfx-sqlclient] DataReader questions -- Moved from [aspngfreeforall] to [ngfx-sqlclient] by Marcie Jones <Click here to reveal e-mail address> -- 1. What method to use when want to specify a fieldname instead of an ordinal? 2. What are e.g. GetSqlInt32, GetSqlChar methods for? Should I use the types fro efficiency's sake when using SQL Server? * code snippets appreciated | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT Reply to this message...        Bob Herrmann Label1.Text = dr("CustomerName") Where dr is the name of your datareader and CustomerName is a column name in the table you accesssed with the datareader. ----- Original Message ----- From: "Bill Bassler" <Click here to reveal e-mail address> To: "ngfx-sqlclient" <Click here to reveal e-mail address> Sent: Tuesday, July 09, 2002 12:59 PM Subject: [ngfx-sqlclient] DataReader questions > -- Moved from [aspngfreeforall] to [ngfx-sqlclient] by Marcie Jones <Click here to reveal e-mail address> -- [Original message clipped] Reply to this message...        Bill Bassler I'm using the SqlDataReader class. The .GetString method for example appear to only take an integer argument as a parameter. e.g private SqlDataReader m_dr; sn = m_dr.GetString("sn"); Build error: Argument '1': cannot convert from 'string' to 'int' where as: private SqlDataReader m_dr; sn = m_dr.GetString(0); compiles fine. Am I missing something? "Bill Bassler" <Click here to reveal e-mail address> wrote in message news:681037@ngfx-sqlclient... [Original message clipped] Reply to this message...        ToddC@match.com You are using C#, The complier may bee cool with it, but I don't the app will. Try this instead: private SqlDataReader m_dr; sn = m_dr.GetString["sn"]; Build error: Argument '1': cannot convert from 'string' to 'int' where as: private SqlDataReader m_dr; sn = m_dr.GetString[0]; tc -----Original Message----- From: Bill Bassler [mailto:Click here to reveal e-mail address] Sent: Tuesday, July 09, 2002 2:59 PM To: ngfx-sqlclient Subject: [ngfx-sqlclient] Re: DataReader questions I'm using the SqlDataReader class. The .GetString method for example appear to only take an integer argument as a parameter. e.g private SqlDataReader m_dr; sn = m_dr.GetString("sn"); Build error: Argument '1': cannot convert from 'string' to 'int' where as: private SqlDataReader m_dr; sn = m_dr.GetString(0); compiles fine. Am I missing something? "Bill Bassler" <Click here to reveal e-mail address> wrote in message news:681037@ngfx-sqlclient... [Original message clipped] | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT Reply to this message...        Trevor Pinkney He's right. If you read the docs it only takes an int as an argument. -----Original Message----- From: Click here to reveal e-mail address [mailto:Click here to reveal e-mail address] Sent: Tuesday, July 09, 2002 4:19 PM To: ngfx-sqlclient Subject: [ngfx-sqlclient] Re: DataReader questions You are using C#, The complier may bee cool with it, but I don't the app will. Try this instead: private SqlDataReader m_dr; sn = m_dr.GetString["sn"]; Build error: Argument '1': cannot convert from 'string' to 'int' where as: private SqlDataReader m_dr; sn = m_dr.GetString[0]; tc -----Original Message----- From: Bill Bassler [mailto:Click here to reveal e-mail address] Sent: Tuesday, July 09, 2002 2:59 PM To: ngfx-sqlclient Subject: [ngfx-sqlclient] Re: DataReader questions I'm using the SqlDataReader class. The .GetString method for example appear to only take an integer argument as a parameter. e.g private SqlDataReader m_dr; sn = m_dr.GetString("sn"); Build error: Argument '1': cannot convert from 'string' to 'int' where as: private SqlDataReader m_dr; sn = m_dr.GetString(0); compiles fine. Am I missing something? "Bill Bassler" <Click here to reveal e-mail address> wrote in message news:681037@ngfx-sqlclient... [Original message clipped] | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT Reply to this message...        Graham Dobson SDK:You can access each column of the returned row by passing the name or ordinal reference of the column to the DataReader. However, for best performance, the DataReader provides a series of methods that allow you to access column values in their native data types (GetDateTime, GetDouble, GetGuid, GetInt32, and so on). For a list of typed accessor methods, see the OleDbDataReader Class and the SqlDataReader Class. Using the typed accessor methods when the underlying data type is known will reduce the amount of type conversion required when retrieving the column value. Graham -----Original Message----- From: Bill Bassler [mailto:Click here to reveal e-mail address] Sent: Tuesday, July 09, 2002 3:59 PM To: ngfx-sqlclient Subject: [ngfx-sqlclient] Re: DataReader questions I'm using the SqlDataReader class. The .GetString method for example appear to only take an integer argument as a parameter. e.g private SqlDataReader m_dr; sn = m_dr.GetString("sn"); Build error: Argument '1': cannot convert from 'string' to 'int' where as: private SqlDataReader m_dr; sn = m_dr.GetString(0); compiles fine. Am I missing something? "Bill Bassler" <Click here to reveal e-mail address> wrote in message news:681037@ngfx-sqlclient... [Original message clipped] | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT Reply to this message...        Tim Musschoot Hello, I'd do this: private SqlDataReader m_dr; sn = m_dr["sn"].ToString(); int a = int.Parse(m_dr["a_possible_int_field"].ToString()); It works good and fast, but there might be several options... Tim Musschoot AspFriends Moderation Team Click here to reveal e-mail address http://www.aspalliance.com/tim_musschoot -----Oorspronkelijk bericht----- Van: Graham Dobson [mailto:Click here to reveal e-mail address] Verzonden: dinsdag 9 juli 2002 22:27 Aan: ngfx-sqlclient Onderwerp: [ngfx-sqlclient] Re: DataReader questions SDK:You can access each column of the returned row by passing the name or ordinal reference of the column to the DataReader. However, for best performance, the DataReader provides a series of methods that allow you to access column values in their native data types (GetDateTime, GetDouble, GetGuid, GetInt32, and so on). For a list of typed accessor methods, see the OleDbDataReader Class and the SqlDataReader Class. Using the typed accessor methods when the underlying data type is known will reduce the amount of type conversion required when retrieving the column value. Graham -----Original Message----- From: Bill Bassler [mailto:Click here to reveal e-mail address] Sent: Tuesday, July 09, 2002 3:59 PM To: ngfx-sqlclient Subject: [ngfx-sqlclient] Re: DataReader questions I'm using the SqlDataReader class. The .GetString method for example appear to only take an integer argument as a parameter. e.g private SqlDataReader m_dr; sn = m_dr.GetString("sn"); Build error: Argument '1': cannot convert from 'string' to 'int' where as: private SqlDataReader m_dr; sn = m_dr.GetString(0); compiles fine. Am I missing something? "Bill Bassler" <Click here to reveal e-mail address> wrote in message news:681037@ngfx-sqlclient... [Original message clipped] | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT Reply to this message...        William \(Bill\) Vaughn (VIP) The problem (as stated) with referencing the columns returned in the DataReader via a string (that matches the column name) is one of performance. My tests show a 1000 vs 234 difference. That is     Myint = cint(dr("au_id") took 1000 units While     Myint = dr.GetInt32(0) too 234 units. By changing the integer ordinal to an enumeration you get the human readability back. William (Bill) Vaughn Author, trainer, mentor Beta V Corporation Redmond, Washington USA www.betav.com (425) 556-9205 (v/f) -----Original Message----- From: Tim Musschoot [mailto:Click here to reveal e-mail address] Sent: Tuesday, July 09, 2002 2:45 PM To: ngfx-sqlclient Subject: [ngfx-sqlclient] Re: DataReader questions Hello, I'd do this: private SqlDataReader m_dr; sn = m_dr["sn"].ToString(); int a = int.Parse(m_dr["a_possible_int_field"].ToString()); It works good and fast, but there might be several options... Tim Musschoot AspFriends Moderation Team Click here to reveal e-mail address http://www.aspalliance.com/tim_musschoot -----Oorspronkelijk bericht----- Van: Graham Dobson [mailto:Click here to reveal e-mail address] Verzonden: dinsdag 9 juli 2002 22:27 Aan: ngfx-sqlclient Onderwerp: [ngfx-sqlclient] Re: DataReader questions SDK:You can access each column of the returned row by passing the name or ordinal reference of the column to the DataReader. However, for best performance, the DataReader provides a series of methods that allow you to access column values in their native data types (GetDateTime, GetDouble, GetGuid, GetInt32, and so on). For a list of typed accessor methods, see the OleDbDataReader Class and the SqlDataReader Class. Using the typed accessor methods when the underlying data type is known will reduce the amount of type conversion required when retrieving the column value. Graham -----Original Message----- From: Bill Bassler [mailto:Click here to reveal e-mail address] Sent: Tuesday, July 09, 2002 3:59 PM To: ngfx-sqlclient Subject: [ngfx-sqlclient] Re: DataReader questions I'm using the SqlDataReader class. The .GetString method for example appear to only take an integer argument as a parameter. e.g private SqlDataReader m_dr; sn = m_dr.GetString("sn"); Build error: Argument '1': cannot convert from 'string' to 'int' where as: private SqlDataReader m_dr; sn = m_dr.GetString(0); compiles fine. Am I missing something? "Bill Bassler" <Click here to reveal e-mail address> wrote in message news:681037@ngfx-sqlclient... [Original message clipped] | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT Reply to this message...        Bill Bassler So it appears that my initial assumptions were correct?? The SqlDataReader is designed purely with speed in mind as reference via an ordinal is always going to be faster than a field collection lookup. So that available methods point you in that direction. You just have to be a bit more careful. "William (Bill) Vaughn" <Click here to reveal e-mail address> wrote in message news:681217@ngfx-sqlclient... [Original message clipped] Reply to this message...        Bill Bassler Sure enough. It works my guess is that it's a tad slower. Whether it's 2/3 slower than the test William Vaughn (see this thread) I don't know. Thanks "Tim Musschoot" <Click here to reveal e-mail address> wrote in message news:681183@ngfx-sqlclient... 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bmdmeC1zcWxjbGllbnRdIG1lbWJlciBiaWxsdmFAbndsaW5rLmNvbSA9IFlPVVIgSUQNCgk+IHwg aHR0cDovL3d3dy5hc3BmcmllbmRzLmNvbS9hc3BmcmllbmRzL25nZngtc3FsY2xpZW50LmFzcCA9 DQpKT0lOL1FVSVQNCgk+DQoJPg0KCT4NCgk+DQoJDQoJDQoJDQoJfCBbbmdmeC1zcWxjbGllbnRd IG1lbWJlciBydXNzLm1jY2xlbGxhbmRAc21hcnRvYmp4LmNvbSA9IFlPVVINCklEDQoJfCBodHRw Oi8vd3d3LmFzcGZyaWVuZHMuY29tL2FzcGZyaWVuZHMvbmdmeC1zcWxjbGllbnQuYXNwID0NCkpP SU4vUVVJVA0KCQ0KDQo Reply to this message...        ToddC@match.com Doh!!, your right. GetString() is a method call, and you must use Parenthesis not brackets, and the docs do call for int. My apologies if I lead anyone a astray.... tc -----Original Message----- From: Trevor Pinkney [mailto:Click here to reveal e-mail address] Sent: Tuesday, July 09, 2002 3:20 PM To: ngfx-sqlclient Subject: [ngfx-sqlclient] Re: DataReader questions He's right. If you read the docs it only takes an int as an argument. -----Original Message----- From: Click here to reveal e-mail address [mailto:Click here to reveal e-mail address] Sent: Tuesday, July 09, 2002 4:19 PM To: ngfx-sqlclient Subject: [ngfx-sqlclient] Re: DataReader questions You are using C#, The complier may bee cool with it, but I don't the app will. Try this instead: private SqlDataReader m_dr; sn = m_dr.GetString["sn"]; Build error: Argument '1': cannot convert from 'string' to 'int' where as: private SqlDataReader m_dr; sn = m_dr.GetString[0]; tc -----Original Message----- From: Bill Bassler [mailto:Click here to reveal e-mail address] Sent: Tuesday, July 09, 2002 2:59 PM To: ngfx-sqlclient Subject: [ngfx-sqlclient] Re: DataReader questions I'm using the SqlDataReader class. The .GetString method for example appear to only take an integer argument as a parameter. e.g private SqlDataReader m_dr; sn = m_dr.GetString("sn"); Build error: Argument '1': cannot convert from 'string' to 'int' where as: private SqlDataReader m_dr; sn = m_dr.GetString(0); compiles fine. Am I missing something? "Bill Bassler" <Click here to reveal e-mail address> wrote in message news:681037@ngfx-sqlclient... [Original message clipped] | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT Reply to this message...        ToddC@match.com No, create an enum for the column ID's. Much better than an array. Here is where speed and maintainability don't equal the same thing. In ADO.OLD, I would create enums for the same purpose. It was, and = still is worth the effort. (IMO) not very difficult to keep up with. tc -----Original Message----- From: Russ McClelland [mailto:Click here to reveal e-mail address]=20 Sent: Wednesday, July 10, 2002 10:40 AM To: ngfx-sqlclient Subject: RE: [ngfx-sqlclient] Re: DataReader questions You could create a hashtable with the String name as the key and the = ordinal as the value so that you could use the fast accessors, but then you = have to maintain that list as it evolves over time.=A0 The benefits of speed = don't seem to outweigh the maintenance issues that arise (to me)... -----Original Message-----=20 From: Bill Bassler=20 Sent: Wed 7/10/2002 6:31 AM=20 To: ngfx-sqlclient=20 Cc:=20 Subject: [ngfx-sqlclient] Re: DataReader questions So it appears that my initial assumptions were correct?? The SqlDataReader is designed purely with speed in mind as reference = via an ordinal is always going to be faster than a field collection lookup. So that = available methods point you in that direction. You just have to be a bit more careful. "William (Bill) Vaughn" <Click here to reveal e-mail address> wrote in message news:681217@ngfx-sqlclient... [Original message clipped] | [ngfx-sqlclient] member Click here to reveal e-mail address =3D YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp =3D JOIN/QUIT Reply to this message...        ToddC@match.com Now that I say that, looking at the docs, there is a bunch, well three interfaces that are implemented by the enum class. It does inherit from value type, but the docs say it is not a value type. Seems to me if it inherits from ValueType, then it is of type ValueType (OOP). Would make an interesting exercise to see which is faster to use: Array Enum Int Variables I would suppose that Int variables would be faster, followed by enum, followed by Array, but It would need some testing to proof out. tc -----Original Message----- From: Click here to reveal e-mail address [mailto:Click here to reveal e-mail address] Sent: Wednesday, July 10, 2002 12:14 PM To: ngfx-sqlclient Subject: [ngfx-sqlclient] Re: DataReader questions No, create an enum for the column ID's. Much better than an array. Here is where speed and maintainability don't equal the same thing. In ADO.OLD, I would create enums for the same purpose. It was, and still is worth the effort. (IMO) not very difficult to keep up with. tc -----Original Message----- From: Russ McClelland [mailto:Click here to reveal e-mail address] Sent: Wednesday, July 10, 2002 10:40 AM To: ngfx-sqlclient Subject: RE: [ngfx-sqlclient] Re: DataReader questions You could create a hashtable with the String name as the key and the ordinal as the value so that you could use the fast accessors, but then you have to maintain that list as it evolves over time.  The benefits of speed don't seem to outweigh the maintenance issues that arise (to me)... -----Original Message----- From: Bill Bassler Sent: Wed 7/10/2002 6:31 AM To: ngfx-sqlclient Cc: Subject: [ngfx-sqlclient] Re: DataReader questions So it appears that my initial assumptions were correct?? The SqlDataReader is designed purely with speed in mind as reference via an ordinal is always going to be faster than a field collection lookup. So that available methods point you in that direction. You just have to be a bit more careful. "William (Bill) Vaughn" <Click here to reveal e-mail address> wrote in message news:681217@ngfx-sqlclient... [Original message clipped] | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT Reply to this message...        Minh Truong [Original message clipped] Any ordinal access is going to be faster than a string lookup, whether it be in a DataReader or another collection. A DataReader primary advantage is that it doesn't download all records into memory like a Dataset would. Reply to this message...        Bill Bassler RE: [ngfx-sqlclient] Re: DataReader questionsAll. If you didn't notice, take a look at William (Bill) Vaughn's response for a rough benchmarks. BTW. If you didn't see it, the ToString method for the SqlDataReader will buy you use of a field name instead of ordinal. It seems the SqlDataReader does maintain some sort of enum, array or collection of the returned fieldnames. The "Get" methods just don't seem to directly support its use?? Use at what cost. Unknown. // THIS WORKS private SqlDataReader m_dr; sn = m_dr["sn"].ToString(); <Click here to reveal e-mail address> wrote in message news:681661@ngfx-sqlclient... Now that I say that, looking at the docs, there is a bunch, well three interfaces that are implemented by the enum class. It does inherit from value type, but the docs say it is not a value type. Seems to me if it inherits from ValueType, then it is of type ValueType (OOP). Would make an interesting exercise to see which is faster to use: Array Enum Int Variables I would suppose that Int variables would be faster, followed by enum, followed by Array, but It would need some testing to proof out. tc -----Original Message----- From: Click here to reveal e-mail address [mailto:Click here to reveal e-mail address] Sent: Wednesday, July 10, 2002 12:14 PM To: ngfx-sqlclient Subject: [ngfx-sqlclient] Re: DataReader questions No, create an enum for the column ID's. Much better than an array. Here is where speed and maintainability don't equal the same thing. In ADO.OLD, I would create enums for the same purpose. It was, and still is worth the effort. (IMO) not very difficult to keep up with. tc -----Original Message----- From: Russ McClelland [mailto:Click here to reveal e-mail address] Sent: Wednesday, July 10, 2002 10:40 AM To: ngfx-sqlclient Subject: RE: [ngfx-sqlclient] Re: DataReader questions You could create a hashtable with the String name as the key and the ordinal as the value so that you could use the fast accessors, but then you have to maintain that list as it evolves over time. The benefits of speed don't seem to outweigh the maintenance issues that arise (to me)... -----Original Message----- From: Bill Bassler Sent: Wed 7/10/2002 6:31 AM To: ngfx-sqlclient Cc: Subject: [ngfx-sqlclient] Re: DataReader questions So it appears that my initial assumptions were correct?? The SqlDataReader is designed purely with speed in mind as reference via an ordinal is always going to be faster than a field collection lookup. So that available methods point you in that direction. You just have to be a bit more careful. "William (Bill) Vaughn" <Click here to reveal e-mail address> wrote in message news:681217@ngfx-sqlclient... [Original message clipped] | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT Reply to this message...        ToddC@match.com Correct, Bill has done a bunch of benchmarking and has a great wealth of knowledge. His reference was about the fastest method to access the column using the GetString() method. This method takes a value of type Int. My post was in reference to a human readable way to specify the Int. Bill mentioned using an Enum, and Russ had mentioned using an array. I would imagine that an Enum is much faster than the Array, due mainly because an array doesn't have a provision for looking up an index based on a key. You still have to index the Array to find the Int to stick in the GetString method. You may also need to cast the value from the Array. This is where the Enum would be faster; it basically has an indexing provision, and would not need to be type casted. That being said, it is inherited from Value Type, and implements three interfaces. None of this screams speed, but it also doesn't necessarily mean they are slow either. Your mileage may vary. Since Int is a base type, or rather not a class, it should be faster than the Enum, and not really that much more trouble to keep up with than the Enum. Again, I am theorizing here, and not speaking from hard data. tc -----Original Message----- From: Bill Bassler [mailto:Click here to reveal e-mail address] Sent: Wednesday, July 10, 2002 1:08 PM To: ngfx-sqlclient Subject: [ngfx-sqlclient] Re: DataReader questions RE: [ngfx-sqlclient] Re: DataReader questionsAll. If you didn't notice, take a look at William (Bill) Vaughn's response for a rough benchmarks. BTW. If you didn't see it, the ToString method for the SqlDataReader will buy you use of a field name instead of ordinal. It seems the SqlDataReader does maintain some sort of enum, array or collection of the returned fieldnames. The "Get" methods just don't seem to directly support its use?? Use at what cost. Unknown. // THIS WORKS private SqlDataReader m_dr; sn = m_dr["sn"].ToString(); <Click here to reveal e-mail address> wrote in message news:681661@ngfx-sqlclient... Now that I say that, looking at the docs, there is a bunch, well three interfaces that are implemented by the enum class. It does inherit from value type, but the docs say it is not a value type. Seems to me if it inherits from ValueType, then it is of type ValueType (OOP). Would make an interesting exercise to see which is faster to use: Array Enum Int Variables I would suppose that Int variables would be faster, followed by enum, followed by Array, but It would need some testing to proof out. tc -----Original Message----- From: Click here to reveal e-mail address [mailto:Click here to reveal e-mail address] Sent: Wednesday, July 10, 2002 12:14 PM To: ngfx-sqlclient Subject: [ngfx-sqlclient] Re: DataReader questions No, create an enum for the column ID's. Much better than an array. Here is where speed and maintainability don't equal the same thing. In ADO.OLD, I would create enums for the same purpose. It was, and still is worth the effort. (IMO) not very difficult to keep up with. tc -----Original Message----- From: Russ McClelland [mailto:Click here to reveal e-mail address] Sent: Wednesday, July 10, 2002 10:40 AM To: ngfx-sqlclient Subject: RE: [ngfx-sqlclient] Re: DataReader questions You could create a hashtable with the String name as the key and the ordinal as the value so that you could use the fast accessors, but then you have to maintain that list as it evolves over time. The benefits of speed don't seem to outweigh the maintenance issues that arise (to me)... -----Original Message----- From: Bill Bassler Sent: Wed 7/10/2002 6:31 AM To: ngfx-sqlclient Cc: Subject: [ngfx-sqlclient] Re: DataReader questions So it appears that my initial assumptions were correct?? The SqlDataReader is designed purely with speed in mind as reference via an ordinal is always going to be faster than a field collection lookup. So that available methods point you in that direction. You just have to be a bit more careful. "William (Bill) Vaughn" <Click here to reveal e-mail address> wrote in message news:681217@ngfx-sqlclient... [Original message clipped] | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT Reply to this message...        Minh Truong > BTW. If you didn't see it, the ToString method for the SqlDataReader will [Original message clipped] This is actually not the ToString() of the DataReader. What you're doing here is 1) Get the Object represented by m_dr["sn"] 2) Get the string representation of that object via ToString() 3) Assign that string to variable "sn" I'm not sure how ADO.NET implements the assessor for the DataReader, but if I were to do it, I'd do an array indexer for ordinal access. This would be the fastest way to get a value out of a collection. I'd then implement a field name lookup that returns a field ordinal. Reply to this message...        Alex Dresko If I learned what I learned correctly yesterday, the REASON ordinal access is faster because specifying a string name for the field forces the DataReader to use the reflection APIs to gather information about itself. Just a side note there... :) Alex Dresko Three Point Oh! -----Original Message----- From: Minh Truong [mailto:Click here to reveal e-mail address] Sent: Wednesday, July 10, 2002 1:32 PM To: ngfx-sqlclient Subject: [ngfx-sqlclient] Re: DataReader questions [Original message clipped] an [Original message clipped] Any ordinal access is going to be faster than a string lookup, whether it be in a DataReader or another collection. A DataReader primary advantage is that it doesn't download all records into memory like a Dataset would. | [ngfx-sqlclient] member Click here to reveal e-mail address = YOUR ID | http://www.aspfriends.com/aspfriends/ngfx-sqlclient.asp = JOIN/QUIT Reply to this message...     System.Data.OleDb.OleDbDataReader System.Data.SqlClient.SqlDataReader System.ValueType Ad MBR BootFX Best-of-breed application framework for .NET projects, developed by Matthew Baxter-Reynolds and MBR IT

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