Database Discussion Boards

Tom Wright4-Mar-05 5:54

4-Mar-05 5:54

I have a field set with a type of datetime size 8. When I run an SQL statement like this

SELECT     TOP 1 MDC1_DATA_TEXT, MDC1_REV_DATE<br />
FROM         MDC1<br />
WHERE     (MDC1_I_O = 'O')

thru the qurey analyzer I get this:

2005-02-25 16:12:07.373

When I run the statement thru enterprise manager by right clicking on the table and choosing open table return all rows then clicking on the SQL button in the toolbar and running my statement, I get this:

2/25/2005 4:12:07 PM

This is the same thing that comes across when I run my SQL statement in my program. The problem is that this "2/25/2005 4:12:07 PM" does not contain milliseconds which is part of the primary key and needed to delete the record after reading it in. Does anyon know how to have SQL return back the other date time stamp?

Here is my code that I'm using in my program:

<br />
	try<br />
	{<br />
		pCommand.CreateInstance(__uuidof(Command));<br />
		pCommand->ActiveConnection = m_pConnection;<br />
		//pCommand->CommandText = _bstr_t("SELECT TOP 1 MDC1_DATA_TEXT, MDC1_REV_DATE FROM MDC1 WHERE (MDC1_I_O = 'O')");<br />
		pCommand->CommandText = _bstr_t("SELECT TOP 1 * FROM MDC1 WHERE (MDC1_I_O = 'O')");<br />
		pRecordset.CreateInstance(__uuidof(Recordset));<br />
		pRecordset->CursorLocation = adUseClient;<br />
		pRecordset->Open((IDispatch*) pCommand, <br />
			vtMissing,<br />
			adOpenStatic,<br />
			adLockBatchOptimistic,<br />
			adCmdUnknown);<br />
		_variant_t MDC1_DATA_TEXT;<br />
		_variant_t MDC1_REV_DATE;<br />
<br />
		while (!pRecordset->adoEOF)<br />
		{<br />
			CString mySQLData = (char*)(_bstr_t)pRecordset->Fields->GetItem("MDC1_DATA_TEXT")->Value;<br />
			//Get the reverse date time stamp so that we can use it for later.<br />
			//MDC1_REV_DATE = pRecordset->GetCollect("MDC1_REV_DATE");<br />
			CString revDate = (char*) (_bstr_t)pRecordset->Fields->GetItem("MDC1_REV_DATE")->Value;<br />

Should I set my pointer for the rev_date to something else?

Thanks

Tom Wright
tawright915@yahoo.com

Re: Date Time shows different

numbrel5-Mar-05 3:45

numbrel

5-Mar-05 3:45

I don't think your problem is SQL, I think it is with how .NET handles DateTime. You might try reading up on DataTime and see how it handles milliseconds. I did a quick search on www.support.microsoft.com and there seem to be a problem with what you want to do.

Re: Date Time shows different

Rob Graham5-Mar-05 12:08

Rob Graham

5-Mar-05 12:08

You are casting it to a string not converting it with a format specifier, so it is going to use default formatting which rounds to seconds. Retain the value as a variant, so that the presison is not lost, use it in a parameterised query when you need to delete.

Beware of string conversions from date time, they are locale dependant, and unless you specify the formating the default precison of the conversion is likely seconds.
SQL servers Date data type is accurate to 3 ms, but will round up: the next values after .373 will be .377 then .380.

Anger is the most impotent of passions. It effects nothing it goes about, and hurts the one who is possessed by it more than the one against whom it is directed.
Carl Sandburg

oracleDataAdapter & Parameters

Gerder3-Mar-05 0:56

Gerder

3-Mar-05 0:56

Hi to all, sorry me for my Inglish.
I have a Problem:
I want to select rows from my Oracle table which named "Table1" and I want to do it with oracleDataAdapter.
It's OK when I use OleDbDataAdapter:
............
command.CommandText="select name from Table1 where num = ?";
Ole.OleDbDataAdapter ada=new Ole.OleDbDataAdapter();
ada.SelectCommand=com;
command.Parameters.Add("@num",Ole.OleDbType.Numeric,3);
command.Parameters[0].Value=1;
............
Can you give me this code with using the oracleDataAdapter and with parameters of oracleConnection.

I had not find the using of oracle parameters in MSDN.At last can you give me Internet resource with the using of oracle in C#.

Thanks.

Gerder

Re: oracleDataAdapter & Parameters

numbrel7-Mar-05 10:38

numbrel

7-Mar-05 10:38

Have you tried using the SQLDataAdapter and just substitute "SQL" for everywhere you have "OleDb"?

insert record into field names that contain brackets

elephantstar2-Mar-05 8:08

elephantstar

2-Mar-05 8:08

Hi there,

I am having difficuly inserting a record into the database. I came to realize that it may be because of my column name that contains brackets. It inserts just fine with other fields that are the same data type but it stops at the bracketed field name. How can I get around this? I can change the column name to exclude any spaces because it's a pre-defined format. I tried bracketing the field name within my code so it's the same as in the design view but it still doesn't work. Can someone help me please. Here's my code below:
----------------------------------------------------------------------------------------------------

COleSafeArray vaFieldList;
vaFieldList.CreateOneDim(VT_VARIANT, 4);

COleSafeArray vaValueArray;
vaValueArray.CreateOneDim(VT_VARIANT, 4);

long lArrayIndex[1];
lArrayIndex[0] = 0;
vaFieldList.PutElement(lArrayIndex, &(_variant_t("NAME")));
lArrayIndex[0] = 1;
vaFieldList.PutElement(lArrayIndex, &(_variant_t("ADDRESS")));
lArrayIndex[0] = 2;
vaFieldList.PutElement(lArrayIndex, &(_variant_t("EMAIL")));
lArrayIndex[0] = 3;
vaFieldList.PutElement(lArrayIndex, &(_variant_t("[NUM CARS]"))); //will not insert this field

lArrayIndex[0] = 0;
vaValueArray.PutElement(lArrayIndex, &(_variant_t(m_name)));
lArrayIndex[0] = 1;
vaValueArray.PutElement(lArrayIndex, &(_variant_t(m_address)));
lArrayIndex[0] = 2;
vaValueArray.PutElement(lArrayIndex, &(_variant_t(m_email)));
lArrayIndex[0] = 3;
vaValueArray.PutElement(lArrayIndex, &(_variant_t(m_num_cars)));

pRecordset->AddNew(vaFieldList, vaValueArray);
pRecordset->Close();

Thanks!

Re: insert record into field names that contain brackets

Michael Potter4-Mar-05 4:23

Michael Potter

4-Mar-05 4:23

If the field name on the Sql Server is actually [NUM CARS] then you would use:

[[Num Cars]]]

If the field name is NUM CARS and you are using the brackets to deal with the space - I don't know what the problem is.

If this does solve your problem then any time you run into the issue again use QUOTENAME()in query analyzer to find the solution.

SELECT QUOTENAME('[NUM CARS]')

Sql Stored Procedure

Mahesh16791-Mar-05 18:40

Mahesh1679

1-Mar-05 18:40

Hi To ALL!

Can any one tell me the max no of input parameter and also output parameter supported in stored procedure (sql server 2000)

Another problem that i face is that i need to convert the sql server 7 database to sql server 2000 database.

Thanks for your valuable help

Mahesh

Re: Sql Stored Procedure

Anonymous1-Mar-05 19:00

Anonymous

1-Mar-05 19:00

A stored procedure can have a maximum of 2,100 parameters

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/tsqlref/ts_create_4hk5.asp[^]

Re: Sql Stored Procedure

Mahesh16791-Mar-05 22:16

Mahesh1679

1-Mar-05 22:16

Thank You Very Much...

You mean 2100 parameters is a combination of input,output,return.

Re: Sql Stored Procedure

Tom Wright4-Mar-05 9:21

Tom Wright

4-Mar-05 9:21

yes the total number.

Tom Wright
tawright915@yahoo.com

OleDbDataAdapter.Update() should throw error but doesn't

Florent Geffroy1-Mar-05 3:37

Florent Geffroy

1-Mar-05 3:37

Hi !

I have a application which use an Access DataBase to store its data. I use an OleDbDataAdapter to update it, everything works fine.

Now, I want to perform some tests, to see what happens in case of errors. The first thing I've tried is when I have not enough space on disk. As I have a VarBinary field in a table, I put inside it a large amount of data.

This is where the problem appears. I add a single DataRow in the table, and then call OleDbDataAdapter.Update() on my table. And no exception is thrown. I know that I have not enough space, but it tells me that the row was updated (although it was not). If I add two rows in the table, it throws the exception on the second row, and it's still telling me that the first one was updated...

Any ideas ? Thanks !

Re: OleDbDataAdapter.Update() should throw error but doesn't

Rob Graham5-Mar-05 12:20

Rob Graham

5-Mar-05 12:20

Access plays some games with storage allocation for Varbinary fields, It likely has an 'unused' varbinary row left over from some previous update that is already allocated but not in use. Compact the database before you run the test, the result will likely be an exception. Access will try to 'recycle' blob storage, so the size of the database file is not the only determining factor in whether or not it can store the update.

Anger is the most impotent of passions. It effects nothing it goes about, and hurts the one who is possessed by it more than the one against whom it is directed.
Carl Sandburg

Re: OleDbDataAdapter.Update() should throw error but doesn't

Florent Geffroy6-Mar-05 21:49

Florent Geffroy

6-Mar-05 21:49

Thanks for replying !

I'll try to compact my database Smile | :)

multiple db systems in one app

schilled1-Mar-05 2:45

schilled

1-Mar-05 2:45

hi,
i've a little db design problem. we are designing an app which should support multiple data storage technologies(sql server, oracle and xml).
because of xml and sql server replication we decided to use a guid column as pk col. but there are some problems.

if use guid:
@ the old version of this app used auto int as pk, so theres no way
to import old databases.
@ oracle doesnt have a guid datatype so we would need to put it into
a different datatype like char or raw but i think it would result
in bad performance

if not use guid:
@ sql server replication is not that easy anymore
@ how do i get a unique id in a xml document??????

does anybody have some hints??
is there another way to get a unique key in a xml doc except guids??

thanks in advance

Re: multiple db systems in one app

-Dr_X-19-Mar-05 16:49

-Dr_X-

19-Mar-05 16:49

The only way I can think of is to create an empty copy of the old database and append the GUID fields to all of the tables. Import the old database then update all of the GUID fields according per their in pk to keep the referencial integrity. It would take some time to create the script to update all of the GUIDs properly but is doable. Then you could import the GUID'd db into the final target db. As far as GUID in oracle as char columns, the performance would most probably suffer but if the columns are indexed properly it shouldn't be that bad.

Michael

I firmly believe that any man's finest hour, the greatest fulfillment of all that he holds dear, is that moment when he has worked his heart out in a good cause and lies exhausted on the field of battle - victorious.
Vince Lombardi (1913-1970)

Re: multiple db systems in one app

schilled20-Mar-05 22:22

schilled

20-Mar-05 22:22

This was also the solution i was thinking of but it seem to be much work. thanks for your reply.

Searching by degree of separation

who2who228-Feb-05 23:19

who2who2

28-Feb-05 23:19

I have an application that lets users search based on degree of separation, so for instance, a user can search for age, hobbies, etc. and limit the search to just users who are 1 degree separate, 2 degrees separate, or 3 degrees separate.

However as it stands now, searches are taking a long long time because according to the programmer, the degree of separation is calculated dynamically upon search, and with a system of about 50,000 users this is taking way over one minute to execute, causing timeouts in the browser.

Is there a better way to go about doing this type of search? Perhaps using a scheduler to perform some calculations beforehand so the searches can use it? Any feedback will be greatly appreciated.

Re: Searching by degree of separation

Michael Potter2-Mar-05 4:03

Michael Potter

2-Mar-05 4:03

There are almost always ways to increase search speed. I usually attempt to trade insert time for select time when queries become to long and other methods (indexes, temp tables) have failed. In your case; when you add a new user you can precalc and store criteria that is necessary for future select statements. This usually will have minor effect on the Insert since it only affects one row in the database whereas, the select statement affects 50,000 rows.

I guess I would need a better description of what 1,2,3 degrees separate means to take this any farther.

Re: Searching by degree of separation

Colin Angus Mackay2-Mar-05 4:33

Colin Angus Mackay

2-Mar-05 4:33

My understanding of "degrees of separation" is:

Jack knows John - 1 degree of separation
John knows Mary - 1 degree of separation
Jack is 2 degrees of separation from Mary.
Mary knows Alice
John is 2 degrees of separation from Alice
Jack is 3 degrees of separation from Alice.

and so on. Someone once calculated that each person is a maximum of 6 degrees of separation from anyone else (I don't know how true that is)

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Extended Stored Procedure from Trigger

samvibes28-Feb-05 20:28

samvibes

28-Feb-05 20:28

I have a Trigger on MSSQL, which calls an Extended Stored Procedure using the exec master..xp_sample where xp_sample is the exported function in the dll. Now the Trigger is written to fire AFTER an INSERT event using either FOR or AFTER. In the DLL a new connection to the DB is made and a query is used to query through the DB to return an xml string. The query is as:

SELECT * FROM Employees FOR XML AUTO

the query is being executed using the function:

retCode = SQLExecDirect(hstmt1, (UCHAR*)"SELECT * FROM Employees FOR XML AUTO", SQL_NTS);

The problem is when I do an INSERT from the Query Analyzer then the trigger is invoked and calls the dll function xp_sample. But the function SQLExecDirect never returns. Looks like it goes into some kind of a deadlock. Can anyone help, please

Re: Extended Stored Procedure from Trigger

Mike Dimmick28-Feb-05 22:57

Mike Dimmick

28-Feb-05 22:57

I'm guessing that your trigger is defined on the Employees table. Since you're creating a new connection, I think the query in your extended stored procedure is deadlocking on the locks held by the INSERT.

Triggers run in the context of the statements that cause them to execute, and significantly, as part of the implicit transaction implied by those statements. An INSERT causes the newly inserted row to be locked with an Exclusive lock. The statement in the XP takes shared locks. When it gets to the newly inserted row, it will block.

The Extended Stored Procedures documentation discusses bound connections, where you can make a new connection part of the original transaction. This might solve your problem.

What are you actually trying to achieve? An XP is really the last resort; you should try to use T-SQL if you can.

Stability. What an interesting concept. -- Chris Maunder

Re: Extended Stored Procedure from Trigger

samvibes28-Feb-05 23:58

samvibes

28-Feb-05 23:58

Hi,
Thanks for the reply, I am looking into it. Basically what I am looking at is whenever I do an INSERT into a Table, I need to Query the Table after the INSERT and send the data via sockets to some client. Now for the sockets implementation I could best think of Extended Stored Procedures where I would Execute a query and then send the data using sockets. This code would go into the dll making the ESP. Could there be a better option, I am not very comfortable with SQL, and would want to have more insight into it. Thanks again, Regards
Samvibes

Re: Extended Stored Procedure from Trigger

Mike Dimmick2-Mar-05 5:58

Mike Dimmick

2-Mar-05 5:58

OK, I can't think of a way to do this in T-SQL! But do you have to do it in the database server? Notification Services[^] looks like it might be able to do what you need.

Developing extended procedures is pretty hard to get right, from what I hear.

Stability. What an interesting concept. -- Chris Maunder

Image data

Murlai28-Feb-05 17:28

Murlai

28-Feb-05 17:28

How can I insert the binary data into image type field in the SQL database with ADO in VC++ project?

Thanks

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