I was asked how to reverse engineer a view so it can be determined what columns and table were used in the sql query to produce the view . So say view 1 was constructed from the following 10 tables and 43 columns . Is this even possible in sql server 2005 ?
Use sp_helptext
exec sp_helptext 'your_view'
Edit
What you want is to find out what dependencies your view has. You can use sp_depends to do that, but it will only get you the table dependencies and not the columns.
exec sp_depends 'your_view'
In order to find out the columns you will probably have to code some kind of SQL parser to extract the columns being used from the Create View statement you recovered with sp_helptext.
You can try using a ReGex to extract the info you want or if you want a big and fancier gun you can try Irony which has a built in Sql Lexic.
Yes, in SSMS choose your database -> views -> right click -> script as CREATE.
If you want to decode a view on another database, you have no access to (e.g interface) - than this is not possible.
Related
Im currently building an app to help with day to day development of our app development team.
Im wondering is there any sort of easy way to generate code to generate SQL tables that have already been created for MSSQL ?
I ask this because in MSSQL you can right click a table and choose the generate scripts option and it will create the code neccessary to build that particular table ?
Is there any way via SQL to leverage that function, or anyway within ColdFusion to create this code, without having to write it from scratch ?
I would use something like this SQL server query to get the list of columns in a table along with Data types, NOT NULL, and PRIMARY KEY constraints to get the table names and columns and data types and construct something with the results to write a script for creating the tables.
You can right click and generate the script from SQL. Then in CF, you can have something like this:-
<cfquery name = "query1" dataSource = "ds1">
type in the generated script from SQL here
</cfquery>`
Say I have written a Create Table script in a query window and run it. So the table got created. Now, where is this script file being generated (system table). I mean if I do a
select * from sys.syscomments
I will get the script for stored procedure or function in the "Text" column. Likewise any way of getting the same for table or view?
Any DMV etc...
Thanks in advance
I'm not sure where the script is stored, but if you're looking to be able to view the scripted language to create the table, in SQL2008 R2 (and I'm pretty sure SQL2008) SSMS can generate the script on the fly. Just select your Table (or View, SP, etc...) and right click. From the context menu, choose Script Table as Create To (or whatever other modification you choose from the list). Then you have a choice of output locations-the New Query Editor Window is probably easiest to see your results. From there you have the base language for that table's creation and you can modify or save it from there.
below query is also works for views
select * from sys.syscomments
For getting script of tables , you have to
Right Click on database >> tasks >> Generate Scripts >> choose objects (select tables)
I think that is the possible way of getting table scripts.
For views you can use the column VIEW_DEFINITION in:
SELECT *
FROM INFORMATION_SCHEMA.VIEWS
I don't think there is an equivalent for tables because tables don't require a stored definition because the table itself is the definition. If you need to copy table structures then the best method is probably to use:
SELECT *
INTO NewTable
FROM OldTable
WHERE 0 = 1
You could try generating your own scripts using the system views and creating dynamic SQL, something like this would get you started
This does not create constraints, and there maybe things I've missed, or cause it to break but the general gist is there. You could also do this outside of SQL as demonstrated quite nicely In this Answer.
HOWEVER I should add I do not condone the use of these methods. There are few scenarios I can think of where it would be necessary to programatically copy a tables structure in this fashion. If it is necessary to copy structures as a one off you'd be better off doing this using the generate script functions that are built into SSMS.
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.
I have a SqlServer db that I would like to port to MySQL. What's the best way to to this. Things that need to be ported are:
Tables (and data)
FileStream → MySQL equivalent?
Stored Procedures
Functions
Data types are relatively similar.
There is no equivalent to FileStream in MySQL - the files must either be stored as BLOBs, or on the file system while the path is stored in the database.
Migrating away from TSQL means:
There's no WITH clause in MySQL - it will have to converted into a derived table/inline view
There's no TOP syntax - these have to be converted to use LIMIT
There's no ranking/analytic functionality in MySQL - can't use ROW_NUMBER, RANK, DENSE_RANK or NTILE. See this article for alternatives.
MySQL views have notoriously limited functionality:
The SELECT statement cannot contain a subquery in the FROM clause.
The SELECT statement cannot refer to system or user variables.
Within a stored program, the definition cannot refer to program parameters or local variables.
The SELECT statement cannot refer to prepared statement parameters.
Any table or view referred to in the definition must exist. However, after a view has been created, it is possible to drop a table or view that the definition refers to. In this case, use of the view results in an error. To check a view definition for problems of this kind, use the CHECK TABLE statement.
The definition cannot refer to a TEMPORARY table, and you cannot create a TEMPORARY view.
Any tables named in the view definition must exist at definition time.
You cannot associate a trigger with a view.
As of MySQL 5.0.52, aliases for column names in the SELECT statement are checked against the maximum column length of 64 characters (not the maximum alias length of 256 characters).
Dynamic SQL will have to be converted to use MySQL's Prepared Statement syntax
A guide/article with some useful tips is available on the official MySQL dev site.
This is not for the faint of heart. Here is an article that explains what you are in for:
http://searchenterpriselinux.techtarget.com/news/column/0,294698,sid39_gci1187176,00.html
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.