I want to run an UPDATE SQL query within a C# foreach loop, such as:
var alterQuery = $#"
IF NOT EXISTS(SELECT 1 FROM sys.columns WHERE Name = 'MyColumn' AND Object_ID = Object_ID('MyTable'))
ALTER TABLE MyTable
ADD [MyColumn] nvarchar(255)
";
using (var connection = myConnection)
{
connection.Execute(alterQuery);
foreach (var obj in myObjects)
{
var query = $#"UPDATE [MyTable]
SET [MyColumn] = '{obj.Val}'
WHERE [ID] = '{obj.ID}'
";
// note: my Execute method uses ExecuteNonQuery() behind the scenes
connection.Execute(query);
}
}
But, I receive the following SQL Exception. I receive it when there are two or more values in myObjects but not when there is only one:
Additional information: Column names in each table must be unique. Column name MyColumn in table MyTable is specified more than once.
I believe it may be due to the queries running simultaneously and trying to access the same column (MyColumn). Should I be running my queries in such a way that each must wait until the previous completes?
How can I successfully run these queries?
I solved this issue by adding BEGIN and END around my ALTER TABLE query.
Does not work:
IF NOT EXISTS(SELECT 1 FROM sys.columns WHERE Name = 'MyColumn' AND
Object_ID = Object_ID('MyTable'))
ALTER TABLE MyTable
ADD [MyColumn] nvarchar(255)
Works:
IF NOT EXISTS(SELECT 1 FROM sys.columns WHERE Name = 'MyColumn' AND
Object_ID = Object_ID('MyTable'))
BEGIN
ALTER TABLE MyTable
ADD [MyColumn] nvarchar(255)
END
I find it weird that in the non-working case, the only line that the IF NOT EXISTScheck controls is the ALTER TABLE MyTable line, rather than both the ALTER TABLE MyTable and the ADD [MyColumn] nvarchar(255) lines, which should be interpreted as one statement.
Related
I have the following trigger:
CREATE TRIGGER insert_or_update_AccountNews
ON AccountNews
INSTEAD OF INSERT
AS
BEGIN
SET NOCOUNT ON;
DECLARE
#AccountNumber bigint,
#NewsId int,
#TariffPlan nvarchar(1024)
SELECT #AccountNumber = INSERTED.AccountNumber,
#NewsId = INSERTED.NewsId,
#TariffPlan = INSERTED.TariffPlan
FROM INSERTED
IF EXISTS (SELECT NewsId FROM [AccountNews]
WHERE AccountNumber = #AccountNumber AND NewsId = #NewsId)
UPDATE [AccountNews]
SET TariffPlan = #TariffPlan
WHERE AccountNumber = #AccountNumber
AND NewsId = #NewsId
ELSE
INSERT INTO [AccountNews] (NewsId, AccountNumber, TariffPlan)
SELECT #NewsId, #AccountNumber, #TariffPlan
END;
And I have a table, as you can see, that is called AccountNews. It has the following columns:
AccountNumber, NewsId, TariffPlan
The idea is when I insert something into the table the trigger will determine if the data exists (I have unique constraint by AccountNumber and NewsId) or not exists. If the data not exists - the insert, otherwise - update.
And it works perfectly via the SQL console, like:
insert into AccountNews (NewsId, AccountId, TariffPlan)
values (12345, 777777, 'Hello world');
insert into AccountNews (NewsId, AccountId, TariffPlan)
values (12345, 777777, 'Hello world 2');
Next, I have this C# code to insert data:
DataTable table = await ReadAsStringAsync(file, newsId);
var connectionString = config.GetConnectionString("MyDbConnection");
using (SqlConnection connection = new SqlConnection(connectionString))
using (SqlBulkCopy bcp = new SqlBulkCopy(connection))
{
connection.Open();
bcp.BatchSize = 1000;
bcp.DestinationTableName = "[dbo].[AccountNews]";
bcp.ColumnMappings.Add("NewsId", "NewsId");
bcp.ColumnMappings.Add("AccountNumber", "AccountNumber");
bcp.ColumnMappings.Add("TariffPlan", "TariffPlan");
bcp.ColumnMappings.Add("Date", "Date");
await bcp.WriteToServerAsync(table);
}
In this case I don't see a result of my trigger. When I load some data that is already in my database I have a unique constraint exception.
To create an UPSERT-only table you can add a trigger like this:
use tempdb
go
drop table if exists AccountNews
create table AccountNews
(
AccountNumber bigint,
NewsId int,
TariffPlan nvarchar(1024),
constraint pk_AccountNews
primary key (AccountNumber, NewsId)
)
go
CREATE TRIGGER insert_or_update_AccountNews
ON AccountNews
INSTEAD OF INSERT
AS
BEGIN
SET NOCOUNT ON;
merge AccountNews as target
using (select * from inserted) as source
on (target.AccountNumber = source.AccountNumber and target.NewsId = source.NewsId)
when matched then
update set TariffPlan = source.TariffPlan
when not matched then
insert (AccountNumber, NewsId, TariffPlan)
values (source.AccountNumber, source.NewsId, source.TariffPlan);
END;
or wihout MERGE (which doen't permit duplicates within a single batch):
CREATE TRIGGER insert_or_update_AccountNews
ON AccountNews
INSTEAD OF INSERT
AS
BEGIN
SET NOCOUNT ON;
with q as
(
select a.*, i.TariffPlan NewTariffPlan
from AccountNews a
join inserted i
on a.AccountNumber = i.AccountNumber
and a.NewsId = i.NewsId
)
update q set TariffPlan = NewTariffPlan;
insert into AccountNews(AccountNumber,NewsId,TariffPlan)
select AccountNumber,NewsId,TariffPlan
from inserted i
where not exists
(
select *
from AccountNews a
where a.AccountNumber = i.AccountNumber
and a.NewsId = i.NewsId
);
END;
go
And you opt-in for triggers and constraint checking with SqlBulkCopyOptions, which you should normally do when bulk loading from an application because bypassing constraints or triggers requires ALTER TABLE privileges on the table.
I'm passing the data through c# to sql stored procedure using dapper.
c# (using dapper):
var dt = new DataTable("dbo.TVPtype");
dt.SetTypeName("dbo.TVPtype");
dt.Columns.Add("ID", typeof(int));
dt.Rows.Add(5);
_db.Execute("mysp", param: new { TVP = dt.AsTableValuedParameter("dbo.TVPtype"), commandType: CommandType.StoredProcedure);
The bellow SQL query will not work and I don't know Why! And it removes all data from mytable.
SQL stored procedure:
CREATE PROCEDURE [dbo].[mysp] #TVP dbo.TVPtype READONLY AS
DELETE FROM [dbo].[mytable] WHERE NOT EXISTS
(
SELECT NULL FROM #TVP na
WHERE ID = na.ID
)
To solve the problem I've used a temporary table in the stored procedure like bellow, and it works well.
My solution using temporary table:
CREATE table temptb (ID int)
insert into temptb select * from #TVP
Now I use temptb instead of #TVP in the delete query:
DELETE FROM [dbo].[mytable] WHERE NOT EXISTS
(
SELECT NULL FROM temptb na
WHERE ID = na.ID
)
It works well and delete specific data (not all data) !
So what's wrong with my first query?
I can't tell you, why it's working with temporary table, but the problem comes from the DELETE statement if you change it to:
DELETE t1
FROM [dbo].[mytable] AS t1 WHERE NOT EXISTS
(
SELECT NULL FROM #TVP na
WHERE t1.ID = na.ID
)
It will work. See, that when I add alias to mytable condition becomes clear which ID's it should compare. When in your example it might compare #TVP ID with it self(that's my guess).
I want to add two more points to your query:
It's better to select something that is not NULL when you check for existence, as NULL is special in SQL(although it is working in your example). For example SELECT 1 FROM #TVP... would be more readable
Why not to do it like this:
Snippet:
DELETE FROM [dbo].[mytable] AS t1 WHERE ID NOT IN
(
SELECT na.ID FROM #TVP na
)
Qualify your column names! You think you are writing:
DELETE FROM [dbo].[mytable]
WHERE NOT EXISTS (SELECT 1
FROM #TVP na
WHERE mytable.ID = na.ID
);
But you are not. The scoping rules of SQL interpret your query as:
DELETE FROM [dbo].[mytable]
WHERE NOT EXISTS (SELECT 1
FROM #TVP na
WHERE na.ID = na.ID
);
This is rather non-sensical. The WHERE is not correlated to the outer query. It will delete either all rows (if #TVP is empty or the ID is always NULL) or no rows (any other situation).
If you qualify all column references, you will never have this problem.
I have over a million records in the list. I pass all records at once from table to stored procedure .In stored procedure i have to have iteration to go thorugh all the rows in the table and for each row it takes table row modified date based on jobid and checks if it exist in database and based on it either it updates or insert the record. I feel that my procedure is not correct, would be glad if someone help on this.
foreach (No_kemi no_list in newforSQL)
{
DataTable _dt = new DataTable("table");
_dt.Columns.Add("JobID", typeof(string));
_dt.Columns.Add("CreatedDate", typeof(datetime));
_dt.Columns.Add("ModifiedDate", typeof(datetime));
_dt.Columns.Add("DbDate", typeof(datetime));
_dt.Columns.Add("SubGUID", typeof(string));
_dt.Columns.Add("eType", typeof(string));
// adding over a million records in the table
_dt.Rows.Add(no_list.ID,no_list.CreatedDate,no_list.ModifiedDate,no_list.DbDate,no_list.SubGUID,no_list.eType);
}
using (SqlCommand sqlCommand = new SqlCommand())
{
sqlCommand.CommandType = CommandType.StoredProcedure;
sqlCommand.CommandText = "Process_NO_table";
sqlCommand.Connection = connection;
SqlParameter typeParam = sqlCmd.Parameters.AddWithValue("#track", _dt);
typeParam .SqlDbType = SqlDbType.Structured;
sqlCmd.ExecuteNonQuery();
}
my tabletype and procedure:
CREATE TYPE TrackType AS TABLE
(
t_Id uniqueidentifier, t_JobID nvarchar(50), t_CreatedDate datetime2(7), t_ModifiedDate datetime2(7), t_DbDate datetime2(7)
t_SubGUID nvarchar(MAX), t_eType nvarchar(MAX)
);
GO
ALTER/CREATE PROCEDURE [dbo].[Process_NO_table] // i will change to alter after i create it
#track TrackType READONLY
AS
// i need to iterate all the rows of the table(over a million)
Declare #rows INT
Declare #i int = 0
Declare #count int = (SELECT COUNT(*) FROM #track)
DECLARE #is INT
WHILE (#i < #count)
BEGIN
-- first i check modified date from the database table
SELECT #is = COUNT(*) FROM NO_table WHERE [JobID] IN (SELECT [t_JobID] FROM #track)
MERGE [dbo].[NO_table] AS [Target]
USING #track AS [Source]
-- if the database modifed date is less than the modifeid date from the proceduretable(#track) then it updates the records
ON [Target].[ModifiedDate] < [Source].[t_ModifiedDate] AND JobID = t_JobID
WHEN MATCHED THEN
UPDATE SET [JobID] = [Source].[t_JobID],
[CreatedDate] = [Source].[t_CreatedDate]
[DbDate]= [Source].[t_DbDate]
[ModifiedDate] = [Source].[t_ModifiedDate]
[SubGUID] = [Source].[t_SubGUID]
[eType] = [Source].[t_eType]
-- if the database modifed dateis not existing then it insert the record
MERGE [dbo].[NO_table] AS [Target]
USING #track AS [Source]
ON (#is != 0)
WHEN NOT MATCHED THEN
INSERT INTO [NO_table] ( [JobID], [CreatedDate], [ModifiedDate], [DbDate], [SubGUID], [eType] )
VALUES ( [Source].[t_JobID], [Source].[t_CreatedDate], [Source].[t_ModifiedDate], [Source].[t_DbDate], [Source].[t_SubGUID], [Source].[t_eType] );
SET #i = #i + 1
END
GO
I think you have a large number of syntax errors in your SQL (assuming MS SQL), but your merge condition is probably giving you the invalid syntax near WHERE, because you need to use AND, not WHERE.
ON [Target].[ModifiedDate] < [Source].[t_ModifiedDate] WHERE JobID = t_JobID
should be
ON [Target].[ModifiedDate] < [Source].[t_ModifiedDate] AND JobID = t_JobID
The Select Top 1 and the WHEN MATCHED THEN after the null check for #dbmoddate need to go away as well, as those are also causing syntax issues.
The insert after the null check for #dbmoddate needs a table specified so it actually knows what to insert into.
You also need to end your merge statement with a semicolon.
UPDATED ANSWER:
Now that you have this more cleaned up, I can better see what you're trying to do. At a high level, you want to simply update existing records where the modified date is less than the modified date of on your custom type. If there does not exist a record in your table that does exist in your custom type, then insert it.
With that said, you don't actually need to loop because you aren't doing anything with your loop. What you currently have and what I'm posting below this is all set-based results, not iterative.
You can make this much simpler by getting rid of the merge statements and doing a simple Update and Insert like I have below. The merge would make more sense if your condition between the two statements was the same (i.e. if you didn't have the check for modified date, then merge would be OK) because then you can use the keywords WHEN MATCHED and WHEN NOT MATCHED and have it in one single merge statement. I personally stay away from MERGE statements because they tend to be a little buggy and there are a number of things you have to watch out for.
I think this solution will be better in the long run as it is easier to read and more maintainable...
CREATE TYPE TrackType AS TABLE
(
t_Id uniqueidentifier, t_JobID nvarchar(50), t_CreatedDate datetime2(7), t_ModifiedDate datetime2(7), t_DbDate datetime2(7)
,t_SubGUID nvarchar(MAX), t_eType nvarchar(MAX)
);
GO
CREATE PROCEDURE [dbo].[Process_NO_table] -- i will change to alter after i create it
#track TrackType READONLY
AS
-- i need to iterate all the rows of the table(over a million)
Update [NO_table]
SET [JobID] = T.[t_JobID],
[CreatedDate] = T.[t_CreatedDate],
[DbDate]= T.[t_DbDate],
[ModifiedDate] = T.[t_ModifiedDate],
[SubGUID] = T.[t_SubGUID] ,
[eType] = T.[t_eType]
From #track T
Where [NO_table].[JobID] = T.[t_JobID]
And [NO_table].[ModifiedDate] < T.[t_ModifiedDate]
Insert [NO_Table]
(
[JobID],
[CreatedDate],
[ModifiedDate],
[DbDate],
[SubGUID],
[eType]
)
Select T.[t_JobID],
T.[t_CreatedDate],
T.[t_ModifiedDate],
T.[t_DbDate],
T.[t_SubGUID],
T.[t_eType]
From #track T
Where Not Exists (Select 1 From [NO_table] where T.[t_JobID] = [NO_table].[JobID])
GO
I have a Gridview in front end where Grid have two columns : ID and Order like this:
ID Order
1 1
2 2
3 3
4 4
Now user can update the order like in front end Gridview:
ID Order
1 2
2 4
3 1
4 3
Now if the user click the save button the ID and order data is being sent to Stored Procedure as #sID = (1,2,3,4) and #sOrder = (2,4,1,3)
Now if I want to update the order and make save I want to store it into database. Through Stored procedure how can update into the table so that the table is updated and while select it gives me the results like:
ID Order
1 2
2 4
3 1
4 3
There is no built in function to parse these comma separated string. However, yo can use the XML function in SQL Server to do this. Something like:
DECLARE #sID VARCHAR(100) = '1,2,3,4';
DECLARE #sOrder VARCHAR(10) = '2,4,1,3';
DECLARE #sIDASXml xml = CONVERT(xml,
'<root><s>' +
REPLACE(#sID, ',', '</s><s>') +
'</s></root>');
DECLARE #sOrderASXml xml = CONVERT(xml,
'<root><s>' +
REPLACE(#sOrder, ',', '</s><s>') +
'</s></root>');
;WITH ParsedIDs
AS
(
SELECT ID = T.c.value('.','varchar(20)'),
ROW_NUMBER() OVER(ORDER BY (SELECT 1)) AS RowNumber
FROM #sIDASXml.nodes('/root/s') T(c)
), ParsedOrders
AS
(
SELECT "Order" = T.c.value('.','varchar(20)'),
ROW_NUMBER() OVER(ORDER BY (SELECT 1)) AS RowNumber
FROM #sOrderASXml.nodes('/root/s') T(c)
)
UPDATE t
SET t."Order" = p."Order"
FROM #tableName AS t
INNER JOIN
(
SELECT i.ID, p."Order"
FROM ParsedOrders p
INNER JOIN ParsedIDs i ON p.RowNumber = i.RowNumber
) AS p ON t.ID = p.ID;
Live Demo
Then you can put this inside a stored procedure or whatever.
Note that: You didn't need to do all of this manually, it should be some way to make this gridview update the underlying data table automatically through data binding. You should search for something like this instead of all this pain.
You could use a table valued parameter to avoid sending delimiter-separated values or even XML to the database. To do this you need to:
Declare a parameter type in the database, like this:
CREATE TYPE UpdateOrderType TABLE (ID int, Order int)
After that you can define the procedure to use the parameter as
CREATE PROCEDURE UpdateOrder (#UpdateOrderValues UpdateOrderType readonly)
AS
BEGIN
UPDATE t
SET OrderID = tvp.Order
FROM <YourTable> t
INNER JOIN #UpdateOrderValues tvp ON t.ID=tvp.ID
END
As you can see, the SQL is trivial compared to parsing XML or delimited strings.
Use the parameter from C#:
using (SqlCommand command = connection.CreateCommand()) {
command.CommandText = "dbo.UpdateOrder";
command.CommandType = CommandType.StoredProcedure;
//create a table from your gridview data
DataTable paramValue = CreateDataTable(orderedData)
SqlParameter parameter = command.Parameters
.AddWithValue("#UpdateOrderValues", paramValue );
parameter.SqlDbType = SqlDbType.Structured;
parameter.TypeName = "dbo.UpdateOrderType";
command.ExecuteNonQuery();
}
where CreateDataTable is something like:
//assuming the source data has ID and Order properties
private static DataTable CreateDataTable(IEnumerable<OrderData> source) {
DataTable table = new DataTable();
table.Columns.Add("ID", typeof(int));
table.Columns.Add("Order", typeof(int));
foreach (OrderData data in source) {
table.Rows.Add(data.ID, data.Order);
}
return table;
}
(code lifted from this question)
As you can see this approach (specific to SQL-Server 2008 and up) makes it easier and more formal to pass in structured data as a parameter to a procedure. What's more, you're working with type safety all the way, so much of the parsing errors that tend to crop up in string/xml manipulation are not an issue.
You can use charindex like
DECLARE #id VARCHAR(MAX)
DECLARE #order VARCHAR(MAX)
SET #id='1,2,3,4,'
SET #order='2,4,1,3,'
WHILE CHARINDEX(',',#id) > 0
BEGIN
DECLARE #tmpid VARCHAR(50)
SET #tmpid=SUBSTRING(#id,1,(charindex(',',#id)-1))
DECLARE #tmporder VARCHAR(50)
SET #tmporder=SUBSTRING(#order,1,(charindex(',',#order)-1))
UPDATE dbo.Test SET
[Order]=#tmporder
WHERE ID=convert(int,#tmpid)
SET #id = SUBSTRING(#id,charindex(',',#id)+1,len(#id))
SET #order=SUBSTRING(#order,charindex(',',#order)+1,len(#order))
END
I am currently working in C#, and I need to insert a new record into one table, get the new primary key value, and then use that as a foreign key reference in inserting several more records. The Database is MS SQL Server 2003. All help is appreciated!
The way to get the identity of the inserted row is with the SCOPE_IDENTITY() function. If you're using stored procedures then this would look something like the following to return the row identity as an output parameter.
CREATE PROCEDURE dbo.MyProcedure
(
#RowId INT = NULL OUTPUT
)
AS
INSERT INTO MyTable
(
Column1
,Column2
,...
)
VALUES
(
#Param1
,#Param2
,...
);
SET #RowId = SCOPE_IDENTITY();
You can then use this value for any subsequent inserts (alternatively, if you can pass the data all into the stored procedure, then you can use it in the remainder of the procedure body).
If you're passing the SQL in dynamically then you use much the same technique, but with a single string with statement delimiters (also ; in SQL), e.g.:
var sql = "INSERT INTO MyTable (Column1, Column2, ...) VALUES (#P1, #P2, ...);" +
"SELECT SCOPE_IDENTITY();";
Then if you execute this using ExecuteScalar you'll be able to get the identity back as the scalar result and cast it to the right type. Alternatively you could build up the whole batch in one go, e.g.
var sql = "DECLARE #RowId INT;" +
"INSERT INTO MyTable (Column1, Column2, ...) VALUES (#P1, #P2, ...);" +
"SET #RowId = SCOPE_IDENTITY();" +
"INSERT INTO MyOtherTable (Column1, ...) VALUES (#P3, #P4, ...);";
This may not be exactly the right syntax, and you may need to use SET NOCOUNT ON; at the start (my mind is rusty as I rarely use dynamic SQL) but it should get you on the right track.
The best way of doing this is the use SCOPE_IDENTITY() function in TSQL. This should be executed as part of the insert i.e.
SqlCommand cmd = new SqlCommand(#"
INSERT INTO T (Name) VALUES(#Name)
SELECT SCOPE_IDENTITY() As TheId", conn);
cmd.AddParameter("#Name", SqlDbType.VarChar, 50).Value = "Test";
int tId = (int)cmd.ExecuteScalar();
Alternatively you can assign SCOPE_IDENTITY() to a variable to be used in successive statements. e.g.
DECLARE #T1 int
INSERT INTO T (Name) VALUES('Test')
SELECT #T1 = SCOPE_IDENTITY()
INSERT INTO T2 (Name, TId) VALUES('Test', #T1)
If you are just using SQL then check Duncan's answer. If however you are using LINQ then you can create the entity, save it to the DB and the ID parameter will be populated automatically.
Given a user entity and a user table it might look like this:
using(var db = new DataContext()) {
var user = new User { Name = "Jhon" };
db.Users.InsertOnSubmit(user);
db.SubmitChanges();
/* At this point the user.ID field will have the primary key from the database */
}