Can AS/400 Database Tables Be Hidden? - database

I was trying to delete a record from a table in AS/400 database. I got an error message saying that there is a referential integrity to another table XYZ in the same Schema ABC.
To my wonder, that table was not in the list of the tables shown by my DbVisualizer database client.
Then I decided to do a select on that table (ABC.XYZ) - but I got the records back. Thinking that it might be a client problem, I used another Client (AS/400 Operations Navigator) - I had the same results: table not on the list, but got the results back when I did a SELECT * FROM ABC.XYZ
My questions is, can the AS/400 tables be hidden in such a manner?
(Please note that the table was not even in the views/system table/Alias/Materialized Query Table)

Tables can be "hidden" via authorities on the object. Do you have *ALLOBJ authority?

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How to use the pre-copy script from the copy activity to remove records in the sink based on the change tracking table from the source?

I am trying to use change tracking to copy data incrementally from a SQL Server to an Azure SQL Database. I followed the tutorial on Microsoft Azure documentation but I ran into some problems when implementing this for a large number of tables.
In the source part of the copy activity I can use a query that gives me a change table of all the records that are updated, inserted or deleted since the last change tracking version. This table will look something like
PersonID Age Name SYS_CHANGE_OPERATION
---------------------------------------------
1 12 John U
2 15 James U
3 NULL NULL D
4 25 Jane I
with PersonID being the primary key for this table.
The problem is that the copy activity can only append the data to the Azure SQL Database so when a record gets updated it gives an error because of a duplicate primary key. I can deal with this problem by letting the copy activity use a stored procedure that merges the data into the table on the Azure SQL Database, but the problem is that I have a large number of tables.
I would like the pre-copy script to delete the deleted and updated records on the Azure SQL Database, but I can't figure out how to do this. Do I need to create separate stored procedures and corresponding table types for each table that I want to copy or is there a way for the pre-copy script to delete records based on the change tracking table?
You have to use a LookUp activity before the Copy Activity. With that LookUp activity you can query the database so that you get the deleted and updated PersonIDs, preferably all in one field, separated by comma (so its easier to use in the pre-copy script). More information here: https://learn.microsoft.com/en-us/azure/data-factory/control-flow-lookup-activity
Then you can do the following in your pre-copy script:
delete from TableName where PersonID in (#{activity('MyLookUp').output.firstRow.PersonIDs})
This way you will be deleting all the deleted or updated rows before inserting the new ones.
Hope this helped!
In the meanwhile the Azure Data Factory provides the meta-data driven copy task. After going through the dialogue driven setup, a metadata table is created, which has one row for each dataset to be synchronized. I solved this UPSERT problem by adding a stored procedure as well as a table type for each dataset to be synchronized. Then I added the relevant information in the metadata table for each row like this
{
"preCopyScript": null,
"tableOption": "autoCreate",
"storedProcedure": "schemaname.UPSERT_SHOP_SP",
"tableType": "schemaname.TABLE_TYPE_SHOP",
"tableTypeParameterName": "shops"
}
After that you need to adapt the sink properties of the copy task like this (stored procedure, table type, table type parameter name):
#json(item().CopySinkSettings).storedProcedure
#json(item().CopySinkSettings).tableType
#json(item().CopySinkSettings).tableTypeParameterName
If the destination table does not exist, you need to run the whole task once before adding the above variables, because auto-create of tables works only as long as no stored procedure is given in the sink properties.

SQL Server - auto-populate field in one table with value from another table in another Database

I have two Azure SQL Server databases with the following as example:
Database Name: DataProp
Table Name: DataImports
Columns: SearchID, SourceID, Text, Status, Country
Database Name: Sources
Table Name: SourceInformation
Columns: SourceID, SourceTitle, Country
Right now, the Country column in the DataProp database is all NULL. I need to auto-populate the Country field in DataProp with the values of the Country fields in the Sources database. The common field between the two tables is SourceID. I need to do this for all existing data, as well as have it occur for future records.
What is the best way to accomplish this? A stored procedure that's set to run on a schedule? If so, I would appreciate guidance on the T-SQL syntax.
As a side-note, I looked at the possibility of a computed column, but this will not work for us b/c we maintain an Azure Search Index on our tables, and Azure Search can't index computed columns.
I don't think you'll be able to directly write a join between tables in two different DBs. We had a similar problem and decided to move all tables into a single DB in separate schemas. I think in your case you can write a Webjob to pull in data from one table and update the second table. I also found one article related to this but haven't personally tried, so not sure if it works.
https://ppolyzos.com/2016/07/30/cross-database-queries-in-azure-sql-databases/

MS Access link to SQL Server - validate input against 2nd table?

I'm trying to think of the easiest way for non-tech users to dump info into a database, without coding my own web application.
Essentially, they are recording subjective phone grading scores for employees.
I linked an Access form to our MS SQL Server database. The only validation I want it -- I want one field, 'employee' - to be validated against a list of employees from say table.employee on SQL Server.
Once the form is submitted it will be written to table.scorecard -- or what have you.
Is this possible in Access? Their standard validation rules don't seem to cover this. Also, is there simply a better way to accomplish this task in general? Thanks
There are two ways to solve this problem.
The simplest is to use a combobox field for your employee information. Use the employee table as the list data source for the combobox and then set the LimitToList property to true. This assumes that you have setup linked table connections for both your employee table and your 'scores' table.
The second solution is to create a foreign key between the employeeId (or whatever the key field is) in the scores table and the employee table on the SQL side. If someone tries to insert an invalid employee, you will get an insert error. Unfortunately, SQL errors tend to be very confusing to most Access users.
If you want to be very through, you could implement both solutions, this would prevent someone going straight to the linked tables and putting in bad data.
I just realized that I am assuming that you are doing proper relational design where the 'scores' table would contain the employeeId rather than a full name. The idea on the form is to have the combobox display the name, but insert the employeeid field.

Dynamically comparing two tables from two different databases and serves in SQL Server Management Studio

I am working on a project, where a user will select a a table choice on a website. Once the table is selected, the website will then connect to the database and select the table from a server (Server A) under a database (ABC). The website will also have to choose the same table from a different server (Server B) under database (DEF). Also these tables will have the same name, they will have some different data entered into them.
Our goal is to come up with a dynamic SQL Query/Stored Procedure. Multiple table choices can be visible in the website and once the user picks an option, it DYNAMICALLY passes that information to the database to find the two tables and yield a final table that portrays the differences.
MY PROBLEM:
I am having a lot of problem with the syntax and doing this process dynamically. I have searched everywhere for a solution and am struggling with this for more than two weeks.
OUTLINE OF MY PLAN:
Find primary keys and the column names of all the columns in a selected table. Pass this information to a temporary table
Create a SQL query with something like :
SET #SQL = select table1.col1, table2.col1... inner join..
Take care of conditions where :
A. Data is present in one table but not the other
B. Data is present in both tables
C. What if there is no data in one or both tables.
I would really appreciate any help. I am very new to SQL and have been trying my hardest in this project for a while. Please help me and I will do my best to repay you. Thank you very much for your time.

inserting into a view in SQL server

I have a SQL Server as backend and use ms access as frontend.
I have two tables (persons and managers), manager is derived from persons (a 1:1 relation), thus i created a view managersFull which is basically a:
SELECT *
FROM `managers` `m`
INNER JOIN `persons` `p`
ON `m`.`id` = `p`.`id`
id in persons is autoincrementing and the primary key, id in managers is the primary key and a foreign key, referencing persons.id
now i want to be able to insert a new dataset with a form in ms access, but i can’t get it to work. no error message, no status line, nothing. the new rows aren’t inserted, and i have to press escape to cancel my changes to get back to design view in ms access.
i’m talking about a managers form and i want to be able to enter manager AND person information at the same time in a single form
my question is now: is it possible what i want to do here? if not, is there a “simple” workaround using after insert triggers or some lines of vba code?
thanks in advance
The problem is that your view is across several tables. If you access multiple tables you could update or insert in only one of them.
Please also check the MSDN for more detailed information on restrictions and on proper strategies for view updates
Assuming ODBC, some things to consider:
make sure you have a timestamp field in the person table, and that it is returned in your managers view. You also probably need the real PK of the person table in the manager view (I'm assuming your view takes the FK used for the self-join and aliases it as the ID field -- I wouldn't do that myself, as it is confusing. Instead, I'd use the real foreign key name in the managers view, and let the PK stand on its own with its real name).
try the Jet/ACE-specific DISTINCTROW predicate in your recordsource. With Jet/ACE back ends, this often makes it possible to insert into both tables when it's otherwise impossible. I don't know for certain if Jet will be smart enough to tell SQL Server to do the right thing, though.
if neither of those things works, change your form to use a recordsource based on your person table, and use a combo box based on the managers view as the control with which you edit the record to relate the person to a manager.
Ilya Kochetov pointed out that you can only update one table, but the work-around would be to apply the updates to the fields on one table and then the other. This solution assumes that the only access you have to these two tables is through this view and that you are not allowed to create a stored procedure to take care of this.
To model and maintain two related tables in access you don’t use a query or view that is a join of both tables. What you do is use a main form, and drop in a sub-form that is based on the child table. If the link master and child setting in the sub-form is set correctly, then you not need to write any code and access will insert the person’s id in the link field.
So, don’t use a joined table here. Simply use a form + sub-form setup and you be able to edit and maintain the data and the data in the related child table.
This means you base the form on the table, and not a view. And you base the sub-form on the child table. So, don't use a view here.

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