On our original design we screwed up a foreign key constraint in our table. Now that the table is full of data we cannot change it without dropping all of the records in the table. The only solution I could think of is to create a backup table and put all of the records in there, then delete all the records, alter the table and start adding them back. Any other (BETTER) ideas? Thanks!
Using MS SQL Server
I'm a bit late, just for reference.
If You are using SQL Server Management Studio, You could generate a DROP and RECREATE script with "Keep schema and data" option.
Right click on the desired DB in object explorer
Tasks > Generate scripts
Select the table you want to script
Then clicking on Advanced button
"Script DROP and CREATE" ->"Script DROP and CREATE"
"Types of data to script" -> "Schema and data"
Hope this helps
Here's some pseudo-code. No need to make a backup table, just make a new table with the right constraint, insert your records into it, and rename.
CREATE TABLE MyTable_2
(...field definitions)
<add the constraint to MyTable_2>
INSERT INTO MyTable_2 (fields)
SELECT fields
FROM MyTable
DROP TABLE MyTable
exec sp_rename 'MyTable2', 'Mytable'
Using SQL Server Management Studio (SSMS), you can use it's table designer to specify the final condition of the table. Before saving the changes, have it generate the change script and save that script. Cancel out of the design window, open the script and review it. SSMS may already have generated a script that does everything you need, fixing the primary-foreign key relationship while preserving all existing data. If not, you will have a script, already started, that performs most of what you need to do and should be able to modify it for your needs.
This is your only solution.
Create the backup table, empty the original one, modify the table and then insert step-by-step until you find a violation.
Update All Schema Database Old by new Schema Database .
Create script (Right click on the desired DB in object explorer Tasks > Generate scripts -> select option select specific database objects and tables ->next -> advanced-> option Type of data to script Data only -> ok ->next ->next.) to data only and backup Database to old database
Drop database old and create new database and make new DB is empty .
Excute script of Old Data only on new database .
Related
In SQL Server Database Engine I have a table named Table A.
I deleted the table using graphical interface, but when I wanted to create a table with same name, the error shows
The object already exists
What is the remedy of this situation?
The following steps should help you track down what is going on and help you create your table:
Right-click on your database and select refresh
Verify that your table does not exist under this database.
If you table is
not shown here, then very likely your table is displayed under the
master database.
To create a table in your selected database,
first select the database and then run your query.
A better
option for number 4, just to be sure you are specifying the correct
database is to run the command use dbname; (where dbname is
the name of your database). Do this on the line above your create table code.
I know you can go into the design view of a table in SQL Server Management Studios and reorder columns as they appear in the design view, however this isn't possible with SQL Azure as the option is disabled. Is there a way to modify SQL Azure tables so that you can reorder their columns as they appear in the design view?
I have been running a number of database upgrades over the last few months to support new requirements and would like to reorder the way the columns appear in design view so they're easier to read, i.e. so they start with a primary key, followed by foreign keys, then normal columns and end with the added by, modified by fields. Its purely to make the tables more readable as I manage them over time.
Just run a script against the table. Its a bit of pseudocode but you should get the idea.
CREATE TABLE TableWithDesiredOrder(PK,FK1,FK2,COL1,COL2)
INSERT INTO TableWithDesiredOrder(PK,FK1,FK2,COL1,COL2....)
SELECT PK,FK1,FK2,COL1,COL2.... FROM OriginalTable
DROP TABLE OriginalTable
Finally Rename the table
sp_Rename TableWithDesiredOrder, OriginalTable
Just another option: I use SQL Delta to propagate my db changes from dev db up to Azure db. So in this case, I just change the col order locally using SSMS GUI, and SQL Delta will do the createnew>copytonew>dropold for me, along with my other local changes. (In Project Options, I set Preserve Column Order=Yes.)
I experienced the same with Azure SQL Database, basically my view changes with ALTER were not taken when did a SELECT * from the view, or the column headers were mixed with the column values.
In order to fix it I dropped the view and re-created it again. That worked.
i have created tables and views, and insrted some test data, but i want to know where i can get the sql code that i used to create and insert the data, i tried to look in the sql history, but its no thier, thanks :))
You can get the SQL required to create and populate the table:
1) For the create table DDL, go to the Tables node and select the table, then click on the SQL tab and copy the DDL it displays.
2) For the insert DML, right-click on the table name in the Tables node and select Export Data then Insert... and fill in the wizard. You can also get the create table DDL this way rather than as I said in step 1.
history F8 should show you everything that has happened in that tab within SQL Developer (for instance file xyz.sql).
if you cannot find the history or the ddl that you wish, you ought to be able to get the ddl 'simply' enough
by
select *
from addmas
where colA = 'my criteria'
;
then clicking F9, then right clicking onto the grid and export data to 'insert'
and that will create the insert statments for you (keep in mind to put in a table name)
to get the CREATE TABLE/VIEW (or object, not the alter tables) you may right click on the table name,
select 'edit' then go down to DDL (create). If you use that tool for your edits it'll also show you the ddl for the alters
I right click on my table in ssms 2008 and select Script Table as / Drop and Create Table to new window and I try to run the script but get an error:
Could not drop table because it is referenced by a foreign key constraint
What was the point of the Drop and Create generate script then?
Thanks,
rod.
The point of the Drop and Create generate script is exactly what you'd think - it gives you an easy way to script out dropping and re-creating a table. However you can't drop a table if other tables reference it via foreign key constraints, which is why you're getting the error message.
If you're just trying to add a column, you can right-click the table in Enterprise Manager and click Modify and just add the column in design view. There's no need to drop the table just to add a column. (And it's especially an awful approach if the table has data in it.)
The easiest way to add a column to an existing table? Write the ALTER TABLE statement yourself instead of relying on SQL Server Management Studio to do it for you:
ALTER TABLE YourTableName
ADD ColumnName int
Whenever I want to add a column to a table it usually goes something like this:
Fire up SQL Server Management Studio (SSMS)
Select "Design" on the table I want to add the column to
Add the new column to the table
Save
Get an error that SSMS can't save because it would need to drop the table (and it can't because the the table has foreign keys on it).
Get frustrated that I forgot that this is something that SSMS can't do
Construct an alter table command by hand to add the column
Move on with life.
This time I am adding a step between numbers 6 and 7. I thought I would ask why SSMS can't make a simple alter table statement to add my new column in.
(In case it matters I am running SSMS 2008 against SQL Server 2008.)
Alternatively, you can go to Tools-->Options-->Designers-->Table and Database Designers and uncheck "Prevent saving changes that require table re-creation"
Problem solved.
Here's an explanation from MSDN: http://support.microsoft.com/default.aspx/kb/956176.
When you change a table so that you
alter the metadata structure of the
table, and then you save the table,
the table must be re-created based on
these changes.