Running a script when a table is updated in Microsoft SQL Server - sql

I recently created a fairly lengthy SQL query script that takes the information of some base tables like forecast, bill of materials, part information and so on to automatically create a production schedule.
The script itself works well, but whenever something in those base tables changes the query script needs to be rerun (the script itself involves first dropping the tables created by the query, and then basically running the longer query of creating and dropping tables to get to the final schedule).
To make things easier on the front end user, my intention was to create a front end through access to allow the users to update the necessary base data.
My question is, is there a way to set something up either through Microsoft SSMS or Access (2016) that would run this script automatically whenever these tables were updated?
My initial search showed a lot of people talking about SQL Server Agent being able to automate queries, but I was not able to find anything regarding running a script when a table is updated, only scheduling things based on time frequency.
Ideally I think the easiest option would be if it were possible on the Access front end to allow the user to run this script by just pushing a button on a form, but I am open to whatever options would achieve the same goal.
Thanks in advance.

Related

Method for updating tables that users are looking at?

I'm looking for a method or solution to allow for a table to be updated that others are running select queries on?
We have an MS SQL Database storing tables which are linked through ODBC to an Access Database front-end.
We're trying to have a query run an update on one of these linked tables but often it is interrupted by users running select statements on the table to look at data though forms inside access.
Is there a way to maybe create a copy of this database table for the users to look at so that the table can still be updated?
I was thinking maybe a transaction but can you perform transactions for select statements? Do they work that way?
The error we get from inside access when we try to run the update while a user has the table open is:
Any help is much appreciated,
Cheers
As a general rule, this should not be occurring. Those reports should not lock nor prevent the sql system from not allowing inserts.
For a quick fix, you can (should) link the reports to some sql server views for their source. And use this for the view:
SELECT * from tblHotels WITH (NOLOCK)
In fact in MOST cases this locking occurs due to combo boxes being driven by a larger table in from SQL server - if the query does not complete (and access has the nasty ability to STOP the flow of data, then you get a sql server table lock).
You also can see the above "holding" of a lock when you launch a form with a LARGE dataset If access does not finish pulling the table/query from SQL server - again a holding lock on the table can remain.
However, I as a general rule NOT seen this occur for reports.
However, it not all clear how the reports are being used and how their data sources are setup.
But, as noted, the quick fix is to create some views for the reports, and use the no-lock hint as per above. That will prevent the tables from holding locks.
Another HUGE idea? For the reports, if they often use some date range or other critera? MAKE 100% sure that sql server has index on the filter or critera. If you don't, then SQL server will scan/lock the whole table. This advice ALSO applies VERY much to say a form in which you filter - put indexing (sql server side) on those common used columns.
And in fact, the notes about the combo box above? We found that JUST adding a indexing to the sort column used in the combo box made most if not all locking issues go away.
Another fix that often works - and requires ZERO changes to the ms-access client side software?
You can change this on the server:
SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED
The above also will in most cases fix the locking issue.

How to regularly update or create a SQL Server table?

I need to collect data from a SQL Server table, format it, and then put it into a different table.
I have access to SQL Server but cannot setup triggers or scheduled jobs.
I can create tables, stored procedures, views and functions.
What can I setup that will automatically collect the data and insert it into a SQL Server table for me?
I would probably create a stored procedure to do this task.
In the stored procedure you can create a CTE or use temp tables (depending on the task) and do all the data manipulation you require and once done, you can use the SELECT INTO statement to move all the data from the temp table into the SQL Server table you need.
https://www.w3schools.com/sql/sql_select_into.asp
You can then schedule this stored procedure to run at a time desired by you
A database is just a storage container. It doesn't "do" things automatically all by itself. Even if you did have the access to create triggers, something would have to happen to the table to cause the trigger to fire, typically a CRUD operation on the parent table. And something external needs to happen to initiate that CRUD operation.
When you start talking about automating a process, you're talking about the function of a scheduler program. SQL Server has one built in, the SQL Agent, and depending on your needs you may find that it's appropriate to enlist help from whoever in your organization does have access to it. I've worked in a couple of organizations, though, that only used the SQL Agent to schedule maintenance jobs, while data manipulation jobs were scheduled through an outside resource. The most common one I've run across is Control-M, but there are other players in that market. I even ran across one homemade scheduler protocol that was just built in C#.NET that worked great.
Based on the limitations you lay out in your question, and the comments you've made in response to others, it sounds to me like you need to do socialize your challenge within your organization to find out what their routine mechanism is for setting up data transfers. It's unlikely that this is the first time it's come up, unless the company was founded in the last week or two. It will probably require that you set up your code, probably a stored procedure or maybe an SSIS package, and then work with someone else, perhaps a DBA or a Site Operations team or some such, to get that process automated to fire when you need it to, whether through an Agent job or maybe a file listener.
Well you have two major options, SP and SSIS.
Both of them can be scheduled to run at a given time with a simple Job from the SQL Server Agent. Keep in mind that if you are doing this on a separate server you might need to add the source server as a Linked Server so you can access it from the script.
I've done this approach in the past and it has worked great. Note, for security reasons, I am not able to access the remote server's task scheduler, so I go through the SQL Server Agent:
Run a SQL Server Agent on a schedule of your choice
Use the SQL Server Agent to call an SSIS Package
The SSIS Package then calls an executable which can pull the data you want from your original table, evaluate it, and then insert a formatted version of it, one record at a time. Alternatively, you can simply create a C# script within the SSIS package via a Script Task.
I hope this helps. Please let me know if you need more details.

SQL - Continuous Integration (Data)

This is a general question and probably there are some solutions already. Most of the things I have found are related to database development, deployment, etc..
I am looking for a process that runs daily and performs some checks against some tables of a database. The data loaded in these tables is loaded by a lot of users, but the idea is that defining some rules, the process will detect "wrong" values loaded by the user.
I know this is a very open question, but do you know if this possible with some tools: Jenkins, DBGhost, etc...?
Thank you,
Kat
You have many options. Here's one train of thought.
Create a table called data_audit with fields like so:
audit_datetime
table
field
wrong_value
rule_violated
issue_description
Create stored procedures/functions that can detect wrong values and store the data into this audit table.
Depending on your database, you can run the stored procedure upon schedule. For example, if you have SQL Server, you can run the job using SQL Agent. Once the job is finished, you can run another job that finds count(*) from audit table for today's date. If count was higher than zero, use Database Mail feature to email relevant people to take action.
If you have a database like MySQL or PostgreSQL, write a short program in a language of your choice (PHP/Python/.NET/whatever) to execute the stored procedure, then do count(*) and then email if count was higher than zero. You can run this program using either cron on Linux or Linux-like systems or Task Scheduler in Windows.
You could use tools like Jenkins to schedule such activity. Task Scheduler/cron are built into your operating system and are easy to use. Additional installation like Jenkins is not necessary. If you already have Jenkins installed, you can certainly piggy-back on it.

SQL: Automatically copy records from one database to another database

I am trying to find out an ideal way to automatically copy new records from one database to another. the databases have different structure! I achieved it by writing VBS scripts which copy the data from one to another and triggered the scripts from another application which passes arguments to the script. But I faced issues at points where there were more than 100 triggers. i.e. 100wscript processes trying to access the database and they couldn't complete the task.
I want to find out a simpler solution inside SQL, I read about setting triggers, Stored procedure and running them from SQL agent, replication etc. The requirement is that I have to copy records to another database periodically or when there is a new record into another database.
Which method will suit me the best?
You can use CDC to do this activity. Create a SSIS package using CDC and run that package periodically through SQL Server Agent Job. CDC will store all the changes of that table and will do all those changes to the destination table when you run the package. Please follow the below link.
http://sqlmag.com/sql-server-integration-services/combining-cdc-and-ssis-incremental-data-loads
The word periodically in your question suggests that you should go for Jobs. You can schedule jobs in SQL Server using Sql Server agent and assign a period. The job will run your script as per assigned frequency.
PrabirS: Change Data Capture
This is a good option. Because it uses the truncation-log to create something similar to the Command Query Segregation Pattern (CQRS).
Alok Gupta: A SQL Job that runs in the SQL Agent
This too is a good option, given that you have something like a modified date thus you can filter the altered data. You can create a Stored Procedure and let it run regularly in the SQL Agent.
A third option could be triggers (the change will happen in the same transaction).
This option is useful for auditing and logging. But you should definitely avoid writing business logic in triggers, as triggers are more or less hidden and occur without directly calling them (similar to CDC actually). I have actually created a trigger about half a year ago that captured the data and inserted it somewhere else in xml-format as the columns in the original table could change over time (multiple projects using the same database(s)).
-Edit-
By the way, your question more or less suggest a lack of a clear design pattern and that the used technique is not the main problem. You could try to read how an ETL-layer is build, or try to implement a "separations of concerns". Note; it is hard to tell if this is the case, but given how you formulated your question, an unclear design is something that pops up in my mind as possible problem.

Queries for migrating data in live database?

I am writing code to migrate data from our live Access database to a new Sql Server database which has a different schema with a reorganized structure. This Sql Server database will be used with a new version of our application in development.
I've been writing migrating code in C# that calls Sql Server and Access and transforms the data as required. I migrated for the first time a table which has entries related to new entries of another table that I have not updated recently, and that caused an error because the record in the corresponding table in SQL Server could not be found
So, my SqlServer productions table has data only up to 1/14/09, and I'm continuing to migrate more tables from Access. So I want to write an update method that can figure out what the new stuff is in Access that hasn't been reflected in Sql Server.
My current idea is to write a query on the SQL side which does SELECT Max(RunDate) FROM ProductionRuns, to give me the latest date in that field in the table. On the Access side, I would write a query that does SELECT * FROM ProductionRuns WHERE RunDate > ?, where the parameter is that max date found in SQL Server, and perform my translation step in code, and then insert the new data in Sql Server.
What I'm wondering is, do I have the syntax right for getting the latest date in that Sql Server table? And is there a better way to do this kind of migration of a live database?
Edit: What I've done is make a copy of the current live database. Which I can then migrate without worrying about changes, then use that to test during development, and then I can migrate the latest data whenever the new database and application go live.
I personally would divide the process into two steps.
I would create an exact copy of Access DB in SQLServer and copy all the data
Copy the data from this temporary SQLServer DB to your destination database
In that way you can write set of SQL code to accomplish second step task
Alternatively use SSIS
Generally when you convert data to a new database that will take it's place in porduction, you shut out all users of the database for a period of time, run the migration and turn on the new database. This ensures no changes to the data are made while doing the conversion. Of course I never would have done this using c# either. Data migration is a database task and should have been done in SSIS (or DTS if you have an older version of SQL Server).
If the databse you are converting to is just in development, I would create a backup of the Access database and load the data from there to test the data loading process and to get the data in so you can do the application development. Then when it is time to do the real load, you just close down the real database to users and use it to load from. If you are trying to keep both in synch wile you develop, well I wouldn't do that but if you must, make a nightly backup of the file and load first thing in the morning using your process.
You may want to look at investing in a tool like SQL Data Compare.
I believe it has support for access databases too, and you can download a trial.
I you are happy with you C# code, but it fails because of the constraints in your destination database you temporarily can disable them and then enable after you copy the whole lot.
I am assuming that your destination database is brand new DB with no data, and not used by anyone when the transfer happens
It sounds like you have two problems:
You're migrating data from one database to another.
You're changing your schema.
Doing either of these things is tricky if you are trying to migrate the data while people are using the data.
The simplest approach is to migrate the data based on a static copy of the data, and also to queue updates to that data from the moment you captured the static copy. I don't know how easy this is in Access, but in SQLServer or Oracle you can use the redo logs for this or a manual solution using triggers. The poor-man's way of doing this is to make triggers for all the relevant tables that log the primary key of the records that have changed. Then after the old database is shut off you can iterate over those keys and get those records from the old database and put them into the new database. Just copy the whole record; if the record was deleted then delete it from the new database.
Your problem is compounded by the fact that you can't simply copy the data, you have to transform it. This means you probably have to shut down both databases and re-migrate the records based on the change list. It will take a lot of planning to ensure you get things right and I'd recommend writing a testing script that can validate that the resulting data is correct.
Also I'd ensure that the code for the migration runs inside one of the databases if possible. Otherwise you are copying the data twice and this will significantly harm the performance.