Database

OleDb?Connection property has not been initialized

4-Dec-08 3:49

No problem Smile | :)

The need to optimize rises from a bad design.My articles[^]

dec821-Dec-08 16:25

dec82

1-Dec-08 16:25

I have this error "ExecuteReader: Connection property has not been initialized."
Here is my code . Could give me any advice to fix it ?Thanks

private void button1_Click(object sender, EventArgs e)
{
string cmd;
string field;
string parameter;
field = "Site,Model";
parameter = "@Site,@Model";

OleDbConnection aConnection = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=c:\\db1.mdb");
cmd = "INSERT INTO Run(" + field + ") values (" + parameter + ")";
OleDbCommand sCommand = new OleDbCommand(cmd);
aConnection.Open();
OleDbDataReader aReader = sCommand.ExecuteReader();

sCommand.Parameters.Add("@Site", OleDbType.VarChar, 20);
sCommand.Parameters.Add("@Model", OleDbType.VarChar, 20);
sCommand.Parameters["@Site"].Value = "site1";
sCommand.Parameters["@Model"].Value = "Model1";

aReader.Close();
aConnection.Close();

}

Re: OleDb?Connection property has not been initialized

Umair Feroze1-Dec-08 17:02

Umair Feroze

1-Dec-08 17:02

Below is the change in bold to do in your code:

private void button1_Click(object sender, EventArgs e)
{
string cmd;
string field;
string parameter;
field = "Site,Model";
parameter = "@Site,@Model";

OleDbConnection aConnection = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=c:\\db1.mdb");
cmd = "INSERT INTO Run(" + field + ") values (" + parameter + ")";
OleDbCommand sCommand = new OleDbCommand(cmd);
aConnection.Open();

sCommand.Connection = aConnection

OleDbDataReader aReader = sCommand.ExecuteReader();

sCommand.Parameters.Add("@Site", OleDbType.VarChar, 20);
sCommand.Parameters.Add("@Model", OleDbType.VarChar, 20);
sCommand.Parameters["@Site"].Value = "site1";
sCommand.Parameters["@Model"].Value = "Model1";

aReader.Close();
aConnection.Close();

}

Hope this solves your problem

Re: OleDb?Connection property has not been initialized

dec821-Dec-08 18:15

dec82

1-Dec-08 18:15

thanks. but another error occur:
No value given for one or more required parameters.???

Re: OleDb?Connection property has not been initialized

Wendelius1-Dec-08 23:18

1-Dec-08 23:18

Why are you creating an OleDbDataReader for an INSERT statement? It makes no sense since reader is used when you fetch data from the database.

Also you execute the command before setting any parameters or their values.

The need to optimize rises from a bad design.My articles[^]

Date Ranges [modified]

mobius1110011-Dec-08 8:43

mobius111001

1-Dec-08 8:43

I'm having a little bit of brain fry going on...

How can I go about to see if any date within a date range is in another date range?

Example: Is any date between 01/01/2008 - 12/31/2015 in 11/21/2008 - 12/21/2009?

MOD:

Ok, so I think I found my answer. Does anyone see an issue with this comparison?

01/01/2008 < 12/21/2009 AND 12/31/2015 > 11/21/2008 [obviously these would be parameters and fields in a database.... paramStart < dbEnd AND paramEnd > dbStart]

modified on Monday, December 1, 2008 3:09 PM

Re: Date Ranges

Wendelius1-Dec-08 9:21

Database updating at clients end

1-Dec-08 9:21

mobius111001 wrote:
Is any date between 01/01/2008 - 12/31/2015 in 11/21/2008 - 12/21/2009?

date1 = 01/01/2008 
date2 = 12/31/2015 
date3 = 11/21/2008 
date4 = 12/21/2009

then it would be something like:

... date1 between date3 and date4 
or  date2 between date3 and date4
or  (date1 < date3 and date2 > date4) ...

The need to optimize rises from a bad design.My articles[^]

singhdheeraj2130-Nov-08 23:42

singhdheeraj21

30-Nov-08 23:42

We have developed software in .net application and backhand as a SQL Server Desktop Engine. The query is how to update database at client end without disturing his live data. There is continious update going on in database structure. This is the issue we have been facing from a long time.
Thanks.

Re: Database updating at clients end

Umair Feroze1-Dec-08 1:41

Umair Feroze

1-Dec-08 1:41

Dear singhdheeraj21,

The best practice is to apply patches after the deployment of the application. While creating a patch keep the versioning of the patches and optionally keep the versioning of the database too. Always create a roll back patch as your last resort. It will help you to recover your last best working state.

Hope this answer your question.

Thanks and Regards,
Umair Feroze

Re: Database updating at clients end

Ashfield1-Dec-08 4:19

Ashfield

1-Dec-08 4:19

The usual way is to make all your database changes repeatable, for example always try and do alter table scripts after checking the column defintion needs changing. A tip, if you make the change through enterpirse manager there is an option to create a change script. These sometimes can be tweaked, but they are the script that would be applied if you said save.

Hope this helps

Bob
Ashfield Consultants Ltd

Extendex Properties In Sql Server 2005

ais0729-Nov-08 23:53

ais07

29-Nov-08 23:53

What Are Extended Properties Sql Server 2005 And What Should I Do To See Extended Properties In Sql Server 2005.I Searched In MSDN I Tried The Method Given Over There To See Extended Properties But Its Not Working
(MSDN:-Select Column Check Properties For Extended Properties)

Re: Extendex Properties In Sql Server 2005

Wendelius30-Nov-08 0:01

30-Nov-08 0:01

Extended properties let you define your own properties on an object and add values to them.

For example you can add extended property Description to a table and then for the value you can define some descriptive text.

Refer to: sp_addextendedproperty (Transact-SQL)[^].

The need to optimize rises from a bad design.My articles[^]

SQL syntax question?

programmervb.netc++29-Nov-08 10:35

programmervb.netc++

29-Nov-08 10:35

I am working in a mySQL db and we made a mistake when implementing the tables by having one of the fields in every table being to short. We use this field to catch which form in the applications update each table. The syntax I am finding is to do this...ALTER TABLE `cl_client_common` change `UpdateProgram` char(50). It is currently a char(20) I know that this will work and we should not lose any data however what I am wanting to accomplish is to do this to every table in the db without having to write the code for all 200+ tables. So what I am wondering is could I write something like ALTER TABLE `databaseName`.`*` change `UpdateProgram` char(50).
Any advice would be much appreciated, Please and Thank you.

Humble Programmer

Wendelius29-Nov-08 11:23

29-Nov-08 11:23

You can use system tables to generate proper statements. It would be something like following:

SELECT CONCAT( 'ALTER TABLE ', Table_Name, ' CHANGE ...') 
FROM Information_Schema.Tables 
WHERE Table_Schema = 'YourSchema';

When executing this select, you'll get statements you can again execute to make the actual changes.

Hope this helps,

Mika

The need to optimize rises from a bad design.My articles[^]

programmervb.netc++29-Nov-08 13:42

programmervb.netc++

29-Nov-08 13:42

Good advice I don't know what that did not cross my mind.

Humble Programmer

programmervb.netc++2-Dec-08 6:50

programmervb.netc++

2-Dec-08 6:50

I used your solution yesterday, it worked perfectly. Thank you very much you are much appreciated.

Humble Programmer

Wendelius2-Dec-08 7:58

2-Dec-08 7:58

You're welcome Smile | :)

The need to optimize rises from a bad design.My articles[^]

sql server instalation

ahawari0928-Nov-08 3:43

ahawari09

28-Nov-08 3:43

Hi,

I have sql server 2005 installed with most of if not all its components, and also have vwd 2008 and VS 2005. Now I am ready to install VS 2008, is it a good method to uninstall sql 2005 and VWD 2008 to start a clean VS 2008 installation?

regards,

hawari

hawari

Wendelius28-Nov-08 3:49

28-Nov-08 3:49

You can install SQL Server 2008 and keep SQL Server 2005 if you need both of them. From my experiences there's been no trouble.

I don't know what you're referring to with VWD?

The need to optimize rises from a bad design.

My articles[^]

Jerry Hammond28-Nov-08 8:08

Jerry Hammond

28-Nov-08 8:08

09 is referring to Visual Web Developer

The world is a stage and most of us are desperately unrehearsed.
—Sean O’Casey, Playwright

Wendelius28-Nov-08 8:34

28-Nov-08 8:34

Ok, thanks for the info! That's something I know nothing about...

The need to optimize rises from a bad design.

My articles[^]

Sqlserver error of date difference

Jerry Hammond28-Nov-08 8:10

Jerry Hammond

28-Nov-08 8:10

No reason to uninstall SQL Server 2005. Not sure why you would need VS 2008 and VWD 2008.

The world is a stage and most of us are desperately unrehearsed.
—Sean O’Casey, Playwright

snehasish28-Nov-08 2:25

snehasish

28-Nov-08 2:25

hi;
i want to write a sql query of different between two dates.
.....................................................
DECLARE @mindays DATETIME
DECLARE @today DATETIME

SET @mindays =select min(daily_date) from r_dailymaterial_entry)
SET @today = getdate()

SELECT DATEDIFF(DAY, @mindays, @today) AS [DateDifference]
.....................................................
i gets a error..
Server: Msg 156, Level 15, State 1, Line 4
Incorrect syntax near the keyword 'select'.

please help me...

Re: Sqlserver error of date difference

Wendelius28-Nov-08 3:43