My scenario:
I can change the ordinal position of a column in a table.Is there a way to change the ordinal position of a column in a table without recreating the table?
No, you have to recreate the table if you wish to achieve this. (SQL SERVER)
Even when you do this in SSMS, you will see that the script that is generated also recreates the table.
Not in SQL Server - Not sure about other RDBMSs.
You can create a View with the desired ordinal positions but the only time I can think that would be useful is if you are using SELECT * which is a practice that should be avoided anyway.
Hi it depends on the database system you use.
For example in some it is possible to remove and add a column and you can do it in a procedure part where you also can refill it.
But in general it shouldn't matter as you can define the returned data order in your select statement. Is not that enough for you?
Without recreating the Table is Not possible. However, if your concern is about loosing the data here is an option provided by SQl Server Management Studio.
Note: I have used Sql Server 2019 Developer Edition.
Right Click on the Table name and Choose Design Option
Using your Cursor Drag the position of your Column to your desired Position
SQlServer Table Design Options
If you want to do it at script level, You can see the idea below provided by SSMS
Enable the "Auto Generate Change Script" Option available in Tools Menu --> Options --> Designers --> Table and Database Designers.
Enabling the Auto Generate Change Script Option
When you drag the Column in SSMS it will automatically creates the Script for you.
The High level Idea in the auto generated Script is,
Creating a Table with Temp_YourTableName with desired Order of Columns
Copying all the Data from the Original Table to new Temp_YourTableName
Drop the Original Table
Renaming the Temp_YourTableName to Original YourTableName
of course doing everything with Transaction scope to avoid any data loss while the script is executing.
I found a good reason why some time we need to do this here. Interestingly, it is based on Context and not to do anything with Technical.
Say for example, Original Address Table Contains, Street Address 1, City, State, Zip and Country columns. If the requirement Changes to include a new Columns like Street Address 2 this would be meaning full.
Related
I want to modify a column name to new name present in a table
but here problem i want to manually modify the column name present in Triggers or SP's.
Is there a any better way of doing it.
To rename a column am using this
sp_RENAME 'Tablename.old_Column', 'new_column' , 'COLUMN';
similarly how can i do it for triggers or SP's.? without opening each script?
Well, there are a bunch of 3rd party tools that are promising this type of "safe rename", some for free and some are not:
ApexSQL has a free tool for that, as MWillemse wrote in his answer,
RedGate have a commercial tool called SQLPrompt that also have a safe renaming feture, However it is far from being free.
Microsoft have a visual studio add-in called SQL Server Data Tools (or SSDT in the short version), as Dan Guzman wrote in his comment.
I have to say I've never tried any of these specific tools for that specific task, but I do have some experience with SSDT and some of RedGate's products and I consider them to be very good tools. I know nothing about ApexSQL.
Another option is to try and write the sql script yourself, However there are a couple of things to take into consideration before you start:
Can your table be accessed directly from outside the sql server? I mean, is it possible that some software is executing sql statement directly on that table? If so, you might break it when you rename that column, and no sql tool will help in this situation.
Are your sql scripting skills really that good? I consider myself to be fairly experienced with sql server, but I think writing a script like that is beyond my skills. Not that it's impossible for me, but it will probably take too much time and effort for something I can get for free.
Should you decide to write it yourself, there are a few articles that might help you in that task:
First, Microsoft official documentation of sys.sql_expression_dependencies.
Second, an article called Different Ways to Find SQL Server Object Dependencies that is written by a 13 years experience DBA,
and last but not least, a related question on StackExchange's Database Administrator's website.
You could, of course, go with the safe way Gordon Linoff suggested in his comment, or use synonyms like destination-data suggested in his answer, but then you will have to manually modify all of the columns dependencies manually, and from what I understand, that is what you want to avoid.
Renaming the Table column
Deleting the Table column
Alter Table Keys
Best way use Database Projects in Visual Studio.
Refer this links
link 1
link 2
you can do what #GorDon suggested.
Apart from this,you can also play with this query,
select o.name, sc.* from sys.syscomments sc inner join sys.objects o
on sc.id=o.object_id where sc.text like '%oldcolumnname%'
this will return list of all proc and trigger.Also you can modify filter to get exact list.then it will be very easy for you to modify,manually.
But whatever you decide,don't simply drop old column.
To be safe,even keep back up.
This suggestion relates to Oracle DB, however there may be equivalent solutions in other DBMS's.
A temporary solution to your issue is to create a pseudocolumn. This solution looks a little hacky because the syntax for a pseudocolumn requires an expression. The simplest expression I can think of is the case statement below. Let me know if you can make it more simple.
ALTER TABLE <<tablename>> ADD (
<<new_column_name>> AS (
CASE
WHEN 1=1 THEN <<tablename>>.<<old_column_name>>
END)
);
This strategy basically creates a new column on the fly by evaluating the case statement and copying the value of <<old_column_value>> to <<new_column_value>>. Because you are dynamically interpolating this column there is a performance penalty vs just selecting the original column.
The one gotcha is that this will only work if you are duplicating a column once. Multiple pseudocolumns cannot contain duplicate expressions in Oracle.
The other strategy you can consider is to create a view and you can name the columns whatever you want. You can even INSERT/UPDATE/DELETE (execute DML) against views, but this would give you a whole new table_name, not just a new column. You could however rename the old table, and name your view the same as your old table. This also has a performance penalty vs just accessing the underlying table.
You might want to replace that text in definition. However, you will be needing a dedicated administrator connection in sql server. Versions also vary in setting up a dedicated administrator connection. Setting up the startup parameter by adding ;-T7806 under advanced. And by adding Admin: before the servername upon logging in. By then, you may be able to modify the value of the definition.
How do I modify a table with SQL Server 2012 in design view? I am not able to alter the table in design view, when I'm done with my changes it gives me the error on the image:
The message error is self explanatory :)
Check the Allow nulls checkbox.
Fill this column with data
then edit the table again and uncheck the allow nulls checkbox
You try to add a new column that must have a value by your definition. But you are not giving a value. Ask yourself: What should the existing records have for that column?
If you can think of a value then add this as default. If not then allow nulls for that column.
(Solve your problem)
To change the Prevent saving changes that require the table re-creation option, follow these steps:
1. Open SQL Server Management Studio (SSMS).
2. On the Tools menu, click Options.
3. In the navigation pane of the Options window, click Designers.
4. Select or clear the Prevent saving changes that require the table re-creation check box, and then click OK.
Note: If you disable this option, you are not warned when you save the table that the changes that you made have changed the metadata structure of the table. In this case, data loss may occur when you save the table.
MORE INFORMATION
visit this link:
https://support.microsoft.com/en-us/kb/956176
I got like 2000 rows of data, when I do select statement I can narrow my query but I cant change any value, as I have to change 50 columns, I dont want to use Update Command as then because values I have to update for each row is unique.
Anyone knows any easier way of selecting data using select command and then edit it.
EDIT
I just went to SQL Management studio, clicked on DB I am working on then find the table, I right clicked on it and then it says "Select top 1000 rows" so Now I can see the query and the data, I added "Where" into query and got what I wanted, but I cant modify the table rows below :S
*Edit 2 *
Or I can develop a Utility that will take Table Name , Column Name and its New value and simply updates it :)
You modify data using an UPDATE statement (with a WHERE clause) in a query window. While Management Studio has a feature called "Edit Top n Rows" that doesn't mean it's a good idea to use it - there are several behavioral bugs that are still unresolved even in the SQL Server 2012 version, and it can also place unnecessary and prohibitive locks on the underlying table.
I know it's not the answer you want to hear, but please become comfortable with proper DML commands. The documentation for UPDATE is found here:
http://msdn.microsoft.com/en-us/library/ms177523(v=sql.100).aspx
The long and short of it, IMHO: If you can identify the rows you want to update by using a SELECT with a WHERE clause, you can also write an UPDATE query using the same WHERE clause.
In SSMS - in the same place you saw "Select top 1000 rows", there should be another option "Open table" or "Edit top 200 Rows" (by default).
If you did that on a table, then pressed the following button:
You should then by able to paste in your select statement you've already written instead of what is there, press the execute button (Red exclamation mark button). The grid that appears is editable.
In general I'd be inclined to agree with #AaronBertrand though, it's better to learn the syntax to Update statements yourself.
If you have Microsoft Access, you can create a linked table to your sql server database and edit it by opening the table and modifying the relevant rows. You can create a query in Microsoft Access as well limiting the rows you want to return, and then you can inline edit the columns you'd like to change in the result set.
See for example here how to create a linked table to SQL Server.
I have a column named Lastmodified, with a data type of Date, but it should have been DateTime.
Is there any way of converting the column?
When I use the 'Design' feature of SQL Server Management Studio I get the following error:
Saving changes is not permitted. The changes you have made require the following
table to be dropped and re-created.
Not really interested in dropping the table, I just want to know if it is possible to convert a column from Date to Datetime or do I have to delete the column and create a new one with the correct data type?
It shouldn't need to drop the table and recreate it, unless that column is taking part in one or more constraints.
You can just do it using SQL:
ALTER TABLE Tab ALTER COLUMN LastModified datetime2 not null
(I chose datetime2 over datetime, since the former is recommended for all new development work, and since the column is currently date, I know you're on SQL Server 2008 or later)
That's just a safety setting in SQL Server Mgmt Studio - you can turn it off, if you're adventurous :-)
Disable the checkbox there and you can do whatever you like!
You can't change the type of a column in place. You need to create a new column, copy of the values over, and then drop the original column.
SQL Management Studio usually accomplishes this by creating a temporary table with the new column name, copying the values over, dropping the original table with the old column, and then renaming the new temporary table to the new name. Often it does this without people even realizing it.
However, this can be a very invasive approach, especially if you already have a lot of rows in the table, so you may want to just write a SQL script add the new column to the table, copy the values over, drop the original column, and then use sp_rename to change the new temporary column name back to the original column name. This is the same idea as what SQL Management Studio is doing, except they are dropping and recreating the whole table, and you are just dropping and recreating the column.
However, if you DO want to let SQL Manangement Studio do it this way, you can turn off that error message. I believe it was originally added because people did not wantdrop and recreate the table by default. To turn this message off, go to Tools->Options-?Designers, and uncheck the "Prevent saving changes that require table re-creation", then you should be able to save your changes in the designer.
In PL/SQL Developer v7.1.x, is there way way to ignore large data types in queries or the "Query Data" feature. For example: If you right click on table FOO, and select "Query Data" this will execute a SELECT * FROM FOO. If that table contains BLOB data the query will take a while to complete and temporarily lock up the application. This is especially problematic when querying remote databases (for obvious reasons).
I would like a way to tell PL/SQL Developer not to retrieve large data by default. I know there is a way to limit the ResultSet size but this doesn't do what I am looking for.
I could just select each column I wanted ignoring certain ones but then I couldn't use the "Query Data" feature.
Thanks.
No, the Query Data feature does one thing and one thing only - queries all the data.
What you might find useful is that you can drag the name of a table or view from the Browser into a SQL Window, choose "Select" from the menu that pops up, and it will generate a SELECT statement on the table with all the column names included - but does not execute the query straight away. You can then edit it however you like (e.g. comment out the LOB columns) before you run it.
I know that Toad has something like that built in, but I'm not aware of a PL/SQL Developer option that disables BLOBS.
The option you are left with, for now, is to simply select all the columns individually and truncate the blob.
ie:
select foo, bar, trunc(baz,100) from foo where ...
Create a View that doesn't contain the blob column or whatever columns you don't routinely want to look at.