In a SQL Server database that I am setting up, there are a few 1 to many tables that I would like to create the "many" table records after the parent record is inserted, inserting only the auto generated ID value and another value from the parent record.
For instance:
Table 1 (Parent): Auto_ID, Name, createby, createdatetime
Table 2 (Child): Auto_ID, Parent_Auto_ID, Col1, Col2, createby, createdatetime
Table 3 (Child): Parent_Auto_ID, Col1, createby, createdatetime
I already have:
CREATE TRIGGER [dbo].[ipamuserInsert]
ON [dbbo].[ipamuser]
FOR INSERT
AS
SET NOCOUNT ON
INSERT INTO [dbo].[ipamuserdefault]
(ipamuserID, homepage, createby, createdatetime)
VALUES
SELECT
ipamuserID,
NULL,
createby,
GETDATE()
FROM
inserted
INSERT INTO [dbo].[ipamextlink]
(ipamuserID, link, createby, GETDATE())
VALUES
SELECT
ipamuserID, null, createby, GETDATE()
FROM
inserted
GO
Is this the right syntax, or do I need to declare a separate temp variable and store the ipamuserID and the createby values and use those instead?
I cant test this without your table definitions but I think that you are spot on.
Depending on the number of tables involved I would consider making this dynamic. The number of tables would have to be high to make it worth the effort though.
Editbased on comment:
You can make this dynamic by using system views to find out what tables are related and generate your Sql dynamically based on the metadata. Here are a couple articles to get you started.
https://msdn.microsoft.com/en-us/library/ms186778.aspx
https://msdn.microsoft.com/en-us/library/ms177862.aspx
The basic structure would be to create a cursor loop for each related table and an inner cursor loop for each column in the related table. You would build the sql statement dynamically in the same format as you have it defined in your question.
Related
I’m trying to create a trigger to change the value of a column in table B if it finds the information in a column in table A.
An example of my database is below:
[TableA],
itemID
[TableB],
itemID
itemInStock
Once a user creates an entry in Table A declaring an itemID, the trigger needs to change the TableB.itemInStock column to ‘Yes’
I’m still learning SQL so excuse me if I’ve missed something, let me know if you need any more info.
I understand there are better ways of doing this but I've been told I need to do this using a trigger.
I've attempted a few different things, but as it stands nothing is working, below is the current solution I have however this updates all itemInStock rows to 'Yes', where as I only want the ones to update where the TableB.itemID matches the itemID entered in TableA.
ALTER TRIGGER [itemAvailability] ON [dbo].[TableA] FOR
INSERT
AS
BEGIN
UPDATE [dbo].[TableB] set itemInStock = 'Yes' WHERE
TableB.itemID = itemID
END
Two problems -
you're not looking at the Inserted pseudo table which contains the
newly inserted rows
you're assuming the trigger is called once per row - this is not the
case, the trigger is called once per statement and the Inserted
pseudo table will contain multiple rows - and you need to deal with
that
So, your code should look like this -
ALTER TRIGGER [itemAvailability] ON [dbo].[TableA]
FOR INSERT
AS
UPDATE TB
SET itemInStock = 'Yes'
FROM [dbo].[TableB] TB JOIN inserted I
on TB.itemID = I.itemID
I have a table called dsReplicated.matDB and a column fee_earner. When that column is updated, I want to record two pieces of information:
dsReplicated.matDB.mt_code
dsReplicated.matDB.fee_earner
from the row where fee_earner has been updated.
I've got the basic syntax for doing something when the column is updated but need a hand with the above to get this over the line.
ALTER TRIGGER [dsReplicated].[tr_mfeModified]
ON [dsReplicated].[matdb]
AFTER UPDATE
AS
BEGIN
IF (UPDATE(fee_earner))
BEGIN
print 'Matter fee earner changed to '
END
END
The problem with triggers in SQL server is that they are called one per SQL statement - not once per row. So if your UPDATE statement updates 10 rows, your trigger is called once, and the Inserted and Deleted pseudo tables inside the trigger each contain 10 rows of data.
In order to see if fee_earner has changed, I'd recommend using this approach instead of the UPDATE() function:
ALTER TRIGGER [dsReplicated].[tr_mfeModified]
ON [dsReplicated].[matdb]
AFTER UPDATE
AS
BEGIN
-- I'm just *speculating* here what you want to do with that information - adapt as needed!
INSERT INTO dbo.AuditTable (Id, TriggerTimeStamp, Mt_Code, Old_Fee_Earner, New_Fee_Earner)
SELECT
i.PrimaryKey, SYSDATETIME(), i.Mt_Code, d.fee_earner, i.fee_earner
FROM Inserted i
-- use the two pseudo tables to detect if the column "fee_earner" has
-- changed with the UPDATE operation
INNER JOIN Deleted d ON i.PrimaryKey = d.PrimaryKey
AND d.fee_earner <> i.fee_earner
END
The Deleted pseudo table contains the values before the UPDATE - so that's why I take the d.fee_earner as the value for the Old_Fee_Earner column in the audit table.
The Inserted pseudo table contains the values after the UPDATE - so that's why I take the other values from that Inserted pseudo-table to insert into the audit table.
Note that you really must have an unchangeable primary key in that table in order for this trigger to work. This is a recommended best practice for any data table in SQL Server anyway.
Ok SQL Server fans I have an issue with a legacy stored procedure that sits inside of a SQL Server 2008 R2 Instance that I have inherited also with the PROD data which to say the least is horrible. Also, I can NOT make any changes to the data nor the table structures.
So here is my problem, the stored procedure in question runs daily and is used to update the employee table. As you can see from my example the incoming data (#New_Employees) contains the updated data and I need to use it to update the data in the Employee data is stored in the #Existing_Employees table. Throughout the years different formatting of the EMP_ID value has been used and must be maintained as is (I fought and lost that battle). Thankfully, I have been successfully in changing the format of the EMP_ID column in the #New_Employees table (Yeah!) and any new records will use this format thankfully!
So now you may see my problem, I need to update the ID column in the #New_Employees table with the corresponding ID from the #Existing_Employees table by matching (that's right you guessed it) by the EMP_ID columns. So I came up with an extremely hacky way to handle the disparate formats of the EMP_ID columns but it is very slow considering the number of rows that I need to process (1M+).
I thought of creating a staging table where I could simply cast the EMP_ID columns to an INT and then back to a NVARCHAR in each table to remove the leading zeros and I am sort of leaning that way but I wanted to see if there was another way to handle this dysfunctional data. Any constructive comments are welcome.
IF OBJECT_ID(N'TempDB..#NEW_EMPLOYEES') IS NOT NULL
DROP TABLE #NEW_EMPLOYEES
CREATE TABLE #NEW_EMPLOYEES(
ID INT
,EMP_ID NVARCHAR(50)
,NAME NVARCHAR(50))
GO
IF OBJECT_ID(N'TempDB..#EXISTING_EMPLOYEES') IS NOT NULL
DROP TABLE #EXISTING_EMPLOYEES
CREATE TABLE #EXISTING_EMPLOYEES(
ID INT PRIMARY KEY
,EMP_ID NVARCHAR(50)
,NAME NVARCHAR(50))
GO
INSERT INTO #NEW_EMPLOYEES
VALUES(NULL, '00123', 'Adam Arkin')
,(NULL, '00345', 'Bob Baker')
,(NULL, '00526', 'Charles Nelson O''Reilly')
,(NULL, '04321', 'David Numberman')
,(NULL, '44321', 'Ida Falcone')
INSERT INTO #EXISTING_EMPLOYEES
VALUES(1, '123', 'Adam Arkin')
,(2, '000345', 'Bob Baker')
,(3, '526', 'Charles Nelson O''Reilly')
,(4, '0004321', 'Ed Sullivan')
,(5, '02143', 'Frank Sinatra')
,(6, '5567', 'George Thorogood')
,(7, '0000123-1', 'Adam Arkin')
,(8, '7', 'Harry Hamilton')
-- First Method - Not Successful
UPDATE NE
SET ID = EE.ID
FROM
#NEW_EMPLOYEES NE
LEFT OUTER JOIN #EXISTING_EMPLOYEES EE
ON EE.EMP_ID = NE.EMP_ID
SELECT * FROM #NEW_EMPLOYEES
-- Second Method - Successful but Slow
UPDATE NE
SET ID = EE.ID
FROM
dbo.#NEW_EMPLOYEES NE
LEFT OUTER JOIN dbo.#EXISTING_EMPLOYEES EE
ON CAST(CASE WHEN NE.EMP_ID LIKE N'%[^0-9]%'
THEN NE.EMP_ID
ELSE LTRIM(STR(CAST(NE.EMP_ID AS INT))) END AS NVARCHAR(50)) =
CAST(CASE WHEN EE.EMP_ID LIKE N'%[^0-9]%'
THEN EE.EMP_ID
ELSE LTRIM(STR(CAST(EE.EMP_ID AS INT))) END AS NVARCHAR(50))
SELECT * FROM #NEW_EMPLOYEES
the number of rows that I need to process (1M+).
A million employees? Per day?
I think I would add a 3rd table:
create table #ids ( id INT not NULL PRIMARY KEY
, emp_id not NULL NVARCHAR(50) unique );
Populate that table using your LTRIM(STR(CAST, ahem, algorithm, and update Employees directly from a join of those three tables.
I recommend using ANSI update, not Microsoft's nonstandard update ... from because the ANSI version prevents nondeterministic results in cases where the FROM produces more than one row.
I am very new to SQL and SQL server, would appreciate any help with the following problem.
I am trying to update a share price table with new prices.
The table has three columns: share code, date, price.
The share code + date = PK
As you can imagine, if you have thousands of share codes and 10 years' data for each, the table can get very big. So I have created a separate table called a share ID table, and use a share ID instead in the first table (I was reliably informed this would speed up the query, as searching by integer is faster than string).
So, to summarise, I have two tables as follows:
Table 1 = Share_code_ID (int), Date, Price
Table 2 = Share_code_ID (int), Share_name (string)
So let's say I want to update the table/s with today's price for share ZZZ. I need to:
Look for the Share_code_ID corresponding to 'ZZZ' in table 2
If it is found, update table 1 with the new price for that date, using the Share_code_ID I just found
If the Share_code_ID is not found, update both tables
Let's ignore for now how the Share_code_ID is generated for a new code, I'll worry about that later.
I'm trying to use a merge query loosely based on the following structure, but have no idea what I am doing:
MERGE INTO [Table 1]
USING (VALUES (1,23-May-2013,1000)) AS SOURCE (Share_code_ID,Date,Price)
{ SEEMS LIKE THERE SHOULD BE AN INNER JOIN HERE OR SOMETHING }
ON Table 2 = 'ZZZ'
WHEN MATCHED THEN UPDATE SET Table 1.Price = 1000
WHEN NOT MATCHED THEN INSERT { TO BOTH TABLES }
Any help would be appreciated.
http://msdn.microsoft.com/library/bb510625(v=sql.100).aspx
You use Table1 for target table and Table2 for source table
You want to do action, when given ID is not found in Table2 - in the source table
In the documentation, that you had read already, that corresponds to the clause
WHEN NOT MATCHED BY SOURCE ... THEN <merge_matched>
and the latter corresponds to
<merge_matched>::=
{ UPDATE SET <set_clause> | DELETE }
Ergo, you cannot insert into source-table there.
You could use triggers for auto-insertion, when you insert something in Table1, but that will not be able to insert proper Shared_Name - trigger just won't know it.
So you have two options i guess.
1) make T-SQL code block - look for Stored Procedures. I think there also is a construct to execute anonymous code block in MS SQ, like EXECUTE BLOCK command in Firebird SQL Server, but i don't know it for sure.
2) create updatable SQL VIEW, joining Table1 and Table2 to show last most current date, so that when you insert a row in this view the view's on-insert trigger would actually insert rows to both tables. And when you would update the data in the view, the on-update trigger would modify the data.
Ok I have a question and it is probably very easy but I can not find the solution.
I have 3 tables plus one main tbl.
tbl_1 - tbl_1Name_id
tbl_2- tbl_2Name_id
tbl_3 - tbl_3Name_id
I want to connect the Name_id fields to the main tbl fields below.
main_tbl
___________
tbl_1Name_id
tbl_2Name_id
tbl_3Name_id
Main tbl has a Unique Key for these fields and in the other table, fields they are normal fields NOT NULL.
What I would like to do is that any time when the record is entered in tbl_1, tbl_2 or tbl_3, the value from the main table shows in that field, or other way.
Also I have the relationship Many to one, one being the main tbl of course.
I have a feeling this should be very simple but can not get it to work.
Take a look at SQL Server triggers. This will allow you to perform an action when a record is inserted into any one of those tables.
If you provide some more information like:
An example of an insert
The resulting change you would like
to see as a result of that insert
I can try and give you some more details.
UPDATE
Based on your new comments I suspect that you are working with a denormalized database schema. Below is how I would suggest you structure your tables in the Employee-Medical visit scenario you discussed:
Employee
--------
EmployeeId
fName
lName
EmployeeMedicalVisit
--------------------
VisitId
EmployeeId
Date
Cost
Some important things:
Note that I am not entering the
employees name into the
EmployeeMedicalVisit table, just the EmployeeId. This
helps to maintain data integrity and
complies with First Normal Form
You should read up on 1st, 2nd and
3rd normal forms. Database
normalization is a very imporant
subject and it will make your life
easier if you can grasp them.
With the above structure, when an employee visited a medical office you would insert a record into EmployeeMedicalVisit. To select all medical visits for an employee you would use the query below:
SELECT e.fName, e.lName
FROM Employee e
INNER JOIN EmployeeMedicalVisit as emv
ON e.EployeeId = emv.EmployeeId
Hope this helps!
Here is a sample trigger that may show you waht you need to have:
Create trigger mytabletrigger ON mytable
For INSERT
AS
INSERT MYOTHERTABLE (MytableId, insertdate)
select mytableid, getdate() from inserted
In a trigger you have two psuedotables available, inserted and deleted. The inserted table constains the data that is being inserted into the table you have the trigger on including any autogenerated id. That is how you get the data to the other table assuming you don't need other data at the same time. YOu can get other data from system stored procuders or joins to other tables but not from a form in the application.
If you do need other data that isn't available in a trigger (such as other values from a form, then you need to write a sttored procedure to insert to one table and return the id value through an output clause or using scope_identity() and then use that data to build the insert for the next table.