I'm looking to switch to DACPACs for our database changes, but I'm a bit at a loss about what to do when it comes to more complex database updates. To illustrate what I mean, let me use a simple example that has the same problem.
Say I have a Customer table that is currently live and I want to add a new CustomerType table with a foreign key from Customer to CustomerType. The new column in Customer should be required (not nullable), but should not have a default value.
I want to use some arbitrary formula to setup the initial type for the existing customers upon upgrading. How would I accomplish this using a DACPAC?
The DACPAC will only know there's a new column and will try to add it to the Customer table, which will of course fail because it is required. Setting a default value is undesirable, as is allowing null values.
Since the DACPAC should be usable to upgrade from every state to the latest, I don't see what kind of configuration or pre/post scripts I should setup to make this work.
Various searches have produced a disappointing lack of useful results :(
I hope there's someone here that can help out. Thanks in advance.
The answer will vary a bit depending on how you're planning to deploy the dacpac(s). One common case is having the dacpac replace some collection of T-SQL update scripts that are executed in sequence to update a database schema from one version to the next. In this case you might choose to have one dacpac file for each schema-version of your database and to update a database you would plan to publish the dacpacs in sequence to update a database to the latest version.
In that case, it's possible to use a post-deploy script to fix up the schema as appropriate. For your example scenario, you can model the database in the database project with the new column specified as NULL and without the FK relationship with the new table. Then, in a post-deploy script you can author the T-SQL necessary to execute an UPDATE statement to fill the new table and the new column, an ALTER statement to change the column's type from NULL to NOT NULL, and finally to add the foreign key relationship.
Then moving forward you can remove the post-deploy script and model the new column and table with the proper column type and FK relationship.
I am very new to MS Access and I am struggling with some things that seem like they should be the most basic. I have imported a table of data from Excel and have defined the data types for the fields. I have no problem there, but now I want to make a new table that has as a primary key one of the fields from the imported table. It looks like I can manually create this table, set the relationship, and then go back and type in each record associated with the new primary key, but this seems completely ridiculous. Surely there must be a way to automatically create one record for each unique instance in the matching field from the original table. Yet, I've scrolled through hundreds of pages of Access tutorials and Googled the question and found no satisfactory guidance.
Do I completely misunderstand what Access is all about? How do I create a new table with entries from a field on an existing table? What am I missing?
You don't specify which version of Access you are using, the suggestions listed below apply to 2010, but should be similar is other versions.
You can create new tables from existing tables using either a 'Make Table' option after selecting 'Create' -> 'Query Design', or you can manually create your table first, then use an 'Append' query.
Without knowing the design of your table it's hard to get more descriptive.
Are you populating your new table's primary key ahead of time, or relying on Auto Number to do it (preferred method)?
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.
Huge database in mssql2005 with big codebase depending on the structure of this database.
I have about 10 similar tables they all contain either the file name or the full path to the file. The full path is always dependent on the item id so it doesn't make sense to store it in the database. Getting useful data out of these tables goes a little like this:
SELECT a.item_id
, a.filename
FROM (
SELECT id_item AS item_id
, path AS filename
FROM xMedia
UNION ALL
-- media_path has a different collation
SELECT item_id AS item_id
, (media_path COLLATE SQL_Latin1_General_CP1_CI_AS) AS filename
FROM yMedia
UNION ALL
-- fullPath contains more than just the filename
SELECT itemId AS item_id
, RIGHT(fullPath, CHARINDEX('/', REVERSE(fullPath))-1) AS filename
FROM zMedia
-- real database has over 10 of these tables
) a
I'd like to create a single view of all these tables so that new code using this data-disaster doesn't need to know about all the different media tables. I'd also like use this view for insert and update statements. Obviously old code would still rely on the tables to be up to date.
After reading the msdn page about creating views in mssql2005 I don't think a view with SCHEMABINDING would be enough.
How would I create such an updateable view?
Is this the right way to go?
Scroll down on the page you linked and you'll see a paragraph about updatable views. You can not update a view based on unions, amongst other limitations. The logic behind this is probably simple, how should Sql Server decide on what source table/view should receive the update/insert?
You can modify partitioned views, provided they satisfy certain conditions.
These conditions include having a partitioning column as a part of the primary key on each table, and having a set on non-overlapping check constraints for the partitioning column.
This seems to be not your case.
In your case, you may do either of the following:
Recreate you tables as views (with computed columns) for your legacy soft to work, and refer to the whole table from the new soft
Use INSTEAD OF triggers to update the tables.
If a view is based on multiple base tables, UPDATE statement on the view may or may not work depending on the UPDATE statement. If the UPDATE statement affects multiple base tables, SQL server throws an error. Whereas, if the UPDATE affects only one base table in the view then the UPDATE will work (Not correctly always). The insert and delete statements will always fail.
INSTEAD OF Triggers, are used to correctly UPDATE, INSERT and DELETE from a view that is based on multiple base tables. The following links has examples along with a video tutorial on the same.
INSTEAD OF INSERT Trigger
INSTEAD OF UPDATE Trigger
INSTEAD OF DELETE Trigger
If I'm adding a column to a table in Microsoft SQL Server, can I control where the column is displayed logically in queries?
I don't want to mess with the physical layout of columns on disk, but I would like to logically group columns together when possible so that tools like SQL Server Management Studio list the contents of the table in a convenient way.
I know that I can do this through SQL Management Studio by going into their "design" mode for tables and dragging the order of columns around, but I'd like to be able to do it in raw SQL so that I can perform the ordering scripted from the command line.
You can not do this programatically (in a safe way that is) without creating a new table.
What Enterprise Manager does when you commit a reordering is to create a new table, move the data and then delete the old table and rename the new table to the existing name.
If you want your columns in a particular order/grouping without altering their physical order, you can create a view which can be whatever you desire.
I think what everyone here is missing is that although not everyone has to deal with 10's, 20's, or 1000's instances of the same software system installed throughout the country and world, those of us that design commercially sold software do so. As a result, we expand systems over time, expand tables by adding fields as new capability is needed, and as those fields are identified do belong in an existing table, and as such, over a decade of expanding, growing, adding fields, etc to tables, and then having to work with those tables from design, to support, to sometimes digging into raw data/troubleshooting to debug new functionality bugs, it is incredibly aggravating to not have the primary information you want to see within the first handful of fields, when you may have tables with 30, 40, 50, or even 90 fields, and yes, in a strictly normalized database.
I've often wished I could do this, for this exact reason. But short of doing exactly what SQL does, building a Create Script for a new Table the way I want it, writing the Insert to it, then dropping all existing constraints, relationships, keys, index, etc etc from the existing table and renaming the "new" table back to the old name, and then reading all those keys, relationships, index, etc etc ....
It's not only tedious, time-consuming, but ... in five more years, it will need to happen again.
It's so close to worth that massive amount of work, however the point is, it won't be the last time we need this ability, since our systems will continue to grow, expand, and get fields in a wacked ordered driven by need/design additions.
A majority of developers think from a single system standpoint that serves a single company or very specific hard box market.
The "off-the-shelf" but significantly progressive designers and leaders of development in their market space will always have to deal with this problem, over and over, and would love a creative solution if anyone has one. This could easily save my company a dozen hours a week, just not having to scroll over, or remember where "that" field is in the source data table.
When Management Studio does it, it's creating a temporary table, copying everything across, dropping your original table and renaming the temporary table. There's no simple equivalent T-SQL statement.
If you don't fancy doing that, you could always create a view of the table with the columns in the order you'd like and use that?
Edit: beaten!
If I understand your question, you want to affect what columns are returned first, second, third, etc in existing queries, right?
If all of your queries are written with SELECT * FROM TABLE - then they will show up in the output as they are laid out in SQL.
If your queries are written with SELECT Field1, Field2 FROM TABLE - then the order they are laid out in SQL does not matter.
There is one way, but its only temporarily for the query itself. For example,
Lets say you have 5 tables.
Table is called T_Testing
FirstName, LastName, PhoneNumber, Email, and Member_ID
you want it to list their ID, then Last Name, then FirstName, then Phone then Email.
You can do it as per the Select.
Select Member_ID, LastName, FirstName, PhoneNumber, Email
From T_Testing
Other than that, if you just want the LastName to Show before first name for some reason, you can do it also as follows:
Select LastName, *
From T_Testing
The only thing you wanna be sure that you do is that the OrderBy or Where Function needs to be denoted as Table.Column if you are going to be using a Where or OrderBy
Example:
Select LastName, *
From T_Testing
Order By T_Testing.LastName Desc
I hope this helps, I figured it out because I needed to do this myself.
Script your existing table to a query window.
Run this script against a Test database (remove the Use statement)
Use SSMS to make the column changes you need
Click Generate Change Script (left most and bottommost icon on the
buttonbar, by default)
Use this script against your real table
All the script really does is create a second table table with the desired column orders, copies all your data into it, drops the original table and then renames the secondary table to take its place. This does save you writing it yourself though should you want a deploy script.
It is not possible to change the order of the columns without recreating the whole table. If you have a few instances of the database only, you can use SSMS for this (Select the table and click "design").
In case you have too many instances for a manual process, you should try this script:
https://github.com/Epaminaidos/reorder-columns
It can be done using SQL, by modifying the system tables directly. For example, look here:
Alter table - Add new column in between
However, I would not recommend playing with system tables, unless it's absolutely necessary.
Open your table in SSMS in design mode:
Reorder your columns:
It is important to not save your change.
Click the "Generate Change Script" button:
Now a window will open that contains the script to apply this change:
Copy the text from the window.
In this instance, it generated the following code:
/* To prevent any potential data loss issues, you should review this script in detail before running it outside the context of the database designer.*/
BEGIN TRANSACTION
SET QUOTED_IDENTIFIER ON
SET ARITHABORT ON
SET NUMERIC_ROUNDABORT OFF
SET CONCAT_NULL_YIELDS_NULL ON
SET ANSI_NULLS ON
SET ANSI_PADDING ON
SET ANSI_WARNINGS ON
COMMIT
BEGIN TRANSACTION
GO
CREATE TABLE dbo.Tmp_MyTable
(
Id int NOT NULL,
Name nvarchar(30) NULL,
Country nvarchar(50) NOT NULL
) ON [PRIMARY]
GO
ALTER TABLE dbo.Tmp_MyTable SET (LOCK_ESCALATION = TABLE)
GO
IF EXISTS(SELECT * FROM dbo.MyTable)
EXEC('INSERT INTO dbo.Tmp_MyTable (Id, Name, Country)
SELECT Id, Name, Country FROM dbo.MyTable WITH (HOLDLOCK TABLOCKX)')
GO
DROP TABLE dbo.MyTable
GO
EXECUTE sp_rename N'dbo.Tmp_MyTable', N'MyTable', 'OBJECT'
GO
COMMIT
As you can see, what it does is 1) create a new temporary table, 2) copy the data over to the temporary table, 3) delete the original table and 4) rename the temporary table to the original table's name.