We have a relatively new database project that we have been writing views and stored procedures for over the last 6 months or so.
The database works
The views work
The stored procedures work
However, the general scope of the project has grown considerably since this project was started, and now some of the table names and field names are a little off base.
For example, the main table in the database is called SheetMetalRequest, but the project has grown to where an actual Sheet Metal Request is now but one of the enumerable types of requests. So, the name on this table is misleading to people coming into the project.
In addition to this main table, there are various columns in other tables that need to be changed as well (think SheetMetalRequestID, for example).
The problem with making this change are the 10 different Views and 30 Stored Procedures that are now a part of this database. Naturally, if something gets changed and not everything is changed with it, our working pre production database could take several man hours to get back to a running state.
It would be GREAT if there were a Refactor ability somehow like what exists in Visual Studio.
SELECT SERVERPROPERTY('productversion'), SERVERPROPERTY('productlevel'), SERVERPROPERTY('edition')
productversion | productlevel | edition
10.0.1600.22 | RTM | Standard Edition (64-bit)
If a tool like SSDT does not work for you for whatever reason, you could do this manually at your own pace. Sometimes a "click one button and go home" approach is actually not what you want.
You could start with introducing synonyms, e.g.
CREATE SYNONYM dbo.Requests FOR dbo.SheetMetalRequest;
Now you can refactor your code in pieces, pointing each reference to the new name. When you are confident that you have captured all references (and this won't be easy even with a tool like SSDT, since it can't see code outside of the database - or even code in dynamic SQL inside the current database), you can drop the synonym and rename the table:
BEGIN TRANSACTION;
DROP SYNONYM dbo.Requests;
EXEC sp_rename 'dbo.SheetMetalRequest', 'Requests', 'OBJECT';
COMMIT TRANSACTION
(You'll also want to update all of your modules with sp_refreshsqlmodule in a loop, twice, to make sure you've completely corrected dependencies.)
This would allow you to update different portions of your code (not just views / stored procedures but also middle-tier classes and even front end stuff) to reference the right names, and not have to do it all at once.
Red Gate's SQL Prompt has a 'smart rename' feature, which sounds like is what you are looking for. This will not only rename the object, but also any references to it in other objects. This is a commercial tool from the company I work for, but has a 14-day fully functional evaluation period.
See http://www.red-gate.com/products/sql-development/sql-prompt/features
Related
Where's the best place to store the version of a table in Oracle? Is it possible to store the version in the table itself, e. g. similar to the comment assigned to a table?
I don't think you can store that information in Oracle, except maybe in a comment on the table, but that would be error prone.
But personally I think you shouldn't want to keep track of versions of tables. After all, to get from a version 1 to a version 2, you may need to modify data as well, or other objects like triggers and procedures that use to new version of the table.
So in a way, it's better to version the entire database, so you can 'combine' multiple changes in one atomic version number.
There are different approaches to this, and different tools that can help you with that. I think Oracle even has some built-in feature, but with Oracle, that means that you will be charged gold bars if you use it, so I won't get into that, and just describe the two that I have tried:
Been there, done that: saving schema structure in Git
At some point we wanted to save our database changes in GitHub, where our other source is too.
We've been using Red Gate Source Control for Oracle (and Schema Compare, a similar tool), and have been looking into other similar tools as well. These tools use version control like Git to keep the latest structure of the database, and it can help you get your changes from your development database to scripts folder or VCS, and it can generate migration scripts for you.
Personally I'm not a big fan, because those tools and scripts focus only on the structure of the database (like you would with versioning individual tables). You'd still need to know how to get from version 1 to version 2, and sometimes only adding a column isn't enough; you need to migrate your data too. This isn't covered properly by tools like this.
In addition, I thought they were overall quite expensive for the work that they do, they don't work as easy as promised on the box, and you'd need different tools for different databases.
Working with migrations
A better solution would be to have migration script. You just make a script to get your database from version 1 to version 2, and another script to get it from version 2 to version 3. These migrations can be about table structure, object modifications, or even just data, it doesn't matter. All you need to do is remember which script was executed last, and execute all versions after that.
Executing migrations can be done by hand, or you can simply script it. But there are tools for this as well. One of them is Flyway, a free tool (paid pro support should you need it) that does exactly this. You can feed it SQL scripts from a folder, which are sorted and executed in order. Each script is a 'version'. Meta data about the process is stored in a separate table in your database. The whole process is described in more detail on Flyway's website.
The advantage of this tool is that it's really simple and flexible, because you just write the migration scripts yourself. All the tool does is execute them and keep track of it. And it can do it for all kinds of databases, so you can introduce the same flow for each database you have.
One way is to define a comment on the table:
comment on table your_table is 'some comment';
Then you can read that meta information using all_tab_comments table.
See
How to get table comments via SQL in Oracle?
For further reading, see:
https://docs.oracle.com/cd/B19306_01/server.102/b14200/statements_4009.htm
We've a problem at my company because everyone shares the development oracle database. Thus, if a developer wants to modify a procedure or package, for example, other's application will fail, until this first developer ends his work.
So I thought it will be great if I could create a User in my database for each demand of work within a synonym (or many) for datase objects.
Here comes the example:
I have a demand called D9877, for instance. My work on this demand is to alter a package named MYPCKG. So to start assignment, I first create a Oracle user as D9877 within a synonym for my MYPCKG. This way, any modification will be applied on synonym, without affecting any other developers.
And here are my questions:
Could I do that without my server storage explodes?
How many disk space a oracle synonym takes?
I think your understanding of synonyms is not quite correct.
Synonym is a link on another object. As a shortcut on file on Windows or link on Linux.
To be able to parallel change of some packages you need to make sure that your application could be installed on dedicated schema. You can create local synonyms on you tables (because tables do take space!) from main application schema and compile packages in your schema. Another developers can have their own version of application (i.e. packages, views).
However you need to consider some cases like triggers (it could be tricky to have 2 versions of the trigger on the same table), some dynamic DDL to tables executed by your application, like truncate table and etc.
Synonym takes several bytes of disk space, but it isn't important at all. This approach will not solve this problem.
First of all it seems like you misunderstand what synonym means. It's an other name for the same object. You cannot 'apply modifications to the synonym', but even if you can, you'll modify the object itself.
Sometimes synonyms can be used to distinguish package versions. Say, you have package A; all uses it. You can make packages A_VERSION_1 and A_VERSION_2, public synonym A for A_VERSION_2 and private synonym A for A_VERSION_2. If you do so, you'll can to debug your application with A_VERSION_2 while all others works with A_VERSION_1.
Bad news is this approach does not work too. It works only when you directly call A from your application. But let's imagine we have two packages, A and B (authid definer). B uses A. You call B from your application and you should to modify A. In this case B will never look to your private synonym. You'll be in need to make B_VERSION_2 with it's private synonym too etc. In view of number of intercalls between database objects it's impossible way to use.
My application will be querying a database using Entity Framework. The problem is that the database table structure changes fairly often (a few times a year).
Back in the SQL days, we would store SQL queries in Resource files (.resx) and when any database changes occurred, we could just edit the one resource file and not have to edit any code in the app, recompile, etc.
Are there any good ways to do this with Linq-to-SQL?
Linq2SQL is innately code-based. If your schema is going to change, then the code will need to change.
The only way I can see around this, and still get some of the benefits of linq, is to write everything as Stored Procedures, which you can than add as method to the linq DataContext.
Then, as long as the Name, input parameters and output columns remain the same, you can change what the SP is doing on the database and the code can stay the same.
My task is to make a trigger which will fire when our programmers create, alter, replace or delete triggers in database. It must log their changes to 2 datatables which I made similar to SYS.trigger$ table and added some extra info about user who made changes to them. I copied the principles of logging from already existing audit capability in ERP-system named Galaktika or Galaxy to be simple. However, I encountered a well-famous problem ORA-04089: no one can create triggers on system tables and stuck with it.
Now I'm looking for a way to gently modify my trigger according to database rules. Here is the original code:
CREATE OR REPLACE TRIGGER MRK_AlTrigger$
BEFORE DELETE OR INSERT OR UPDATE
ON SYS.TRIGGER$
REFERENCING NEW AS New OLD AS Old
FOR EACH ROW
DECLARE
Log_Rec MRK_TRIGGERS_LOG_HEADER.NREC%TYPE;
BEGIN
INSERT INTO MRK_TRIGGERS_LOG_HEADER (DATEOFCHANGE,
USERCODE,
OPERATION,
OBJ#)
VALUES (
SYSDATE,
UID,
CASE
WHEN INSERTING THEN 0
WHEN UPDATING THEN 1
WHEN DELETING THEN 2
END,
CASE
WHEN INSERTING OR UPDATING THEN :new.OBJ#
ELSE :old.OBJ#
END)
RETURNING NRec
INTO Log_Rec;
IF INSERTING OR UPDATING
THEN
INSERT INTO MRK_TRIGGERS_LOG_SPECIF (LOGLINK,
OBJ#,
TYPE#,
UPDATE$,
INSERT$,
DELETE$,
BASEOBJECT,
REFOLDNAME,
REFNEWNAME,
DEFINITION,
WHENCLAUSE,
ACTION#,
ACTIONSIZE,
ENABLED,
PROPERTY,
SYS_EVTS,
NTTRIGCOL,
NTTRIGATT,
REFPRTNAME,
ACTIONLINENO)
VALUES (Log_Rec,
:new.OBJ#,
:new.TYPE#,
:new.UPDATE$,
:new.INSERT$,
:new.DELETE$,
:new.BASEOBJECT,
:new.REFOLDNAME,
:new.REFNEWNAME,
:new.DEFINITION,
:new.WHENCLAUSE,
:new.ACTION#,
:new.ACTIONSIZE,
:new.ENABLED,
:new.PROPERTY,
:new.SYS_EVTS,
:new.NTTRIGCOL,
:new.NTTRIGATT,
:new.REFPRTNAME,
:new.ACTIONLINENO);
END IF;
EXCEPTION
WHEN OTHERS
THEN
-- Consider logging the error and then re-raise
RAISE;
END MRK_AlTrigger$;
/
I can also provide MRK_TRIGGERS_LOG_HEADER and MRK_TRIGGERS_LOG_SPECIF DDL, but think it is not necessary. So to make summary, here are the questions I have:
How do I modify the above source to the syntax CREATE OR REPLACE TRIGGER ON DATABASE?
Am I inventing a wheel doing this? Is there any common way to do such things? (I noticed that some tables have logging option, but consider it is for debugging purposes)
Any help will be appreciated!
UPD: I came to decision (thanks to APC) that it is better to hold different versions of code in source control and record only revision number in DB, but dream about doing this automatically.
"We despaired to appeal to our programmers' neatness so my boss
requires that there must be strong and automatic way to log changes.
And to revert them quickly if we need."
In other words, you want a technical fix for what is a political problem. This does not work. However, if you have your boss's support you can sort it out. But it will get messy.
I have been on both sides of this fence, having worked as developer and development DBA. I know from bitter experience how bad it can be if the development database - schemas, configuration parameters, reference data, etc - are not kept under control. Your developers will feel like they are flying right now, but I guarantee you they are not tracking all the changes they make in script form . So their changes are not reversible or repeatable, and when the project reaches UAT the deployment will most likely be a fiasco (buy me a beer and I'll tell you some stories).
So what to do?
Privileged access
Revoke access to SYSDBA accounts and application schema accounts from developers. Apart from anything else you may find parts of the application start to rely on privileged accesses and/or hard-coded passwords, and those are Bad Things; you don't want to include those breaches in Production.
As your developers have got accustomed to having such access this will be highly unpopular. Which is why you need your boss's support. You also must have a replacement approach in place, so leave this action until last. But make no mistake, this is the endgame.
Source control
Database schemas are software too. They are built out of programs, just like the rest of the application, only the source code is DDL and DML scripts not C# or Java. These scripts can be controlled in SVN as with any other source code.
How to organise it in source control? That can be tricky. So recognise that you have three categories of scripts:
Schema scripts which deploy objects
Configuration scripts which insert reference data, manage system parameters, etc
Build scripts which call the other scripts in the right order
Managing the schema scripts is the hardest thing to get right. I suggest you use separate scripts for each object. Also, have separate scripts for table, indexes and constraints. This means you can build all the tables without needing to arrange them in dependency order.
Handling change
The temptation will be to just control a CREATE TABLE statement (or whatever). This is a mistake. In actuality changes to the schema are just as likely to add, drop or modify columns as to introduce totally new objects. Store a CREATE TABLE statement as a baseline, then manage subsequent changes as ALTER TABLE statements.
One file for CREATE TABLE and subsequent ALTER TABLE commands, or separate ones? I'm comfortable having one script: I don't mind if a CREATE TABLE statement fails when I'm expecting the table to already be there. But this can be confusing if others will be running the scripts in say Production. So have a baseline script then separate scripts for applying changes. One alter script per object per time-box is a good compromise.
Changes from developers consist of
alter table script(s) to apply the change
a mirrored alter table script(s) to reverse the change
other scripts, e.g. DML
change reference number (which they will use in SVN)
Because you're introducing this late in the day, you'll need to be diplomatic. So make the change process light and easy to use. Also make sure you check and run the scripts as soon as possible. If you're responsive and do things quickly enough the developers won't chafe under the restricted access.
Getting to there
First of all you need to establish a baseline. Something like DBMS_METADATA will give you CREATE statements for all current objects. You need to organise them in SVN and write the build scripts. Create a toy database and get this right.
This may take some time, so remember to refresh the DDL scripts so they reflect the latest statement. If you have access to a schema comparison tool that would be very handy right now.
Next, sort out the configuration. Hopefully you already know tables contain reference data, otherwise ask the developers.
In your toy database practice zapping the database and building it from scratch. You can use something like Ant or Hudson to automate this if you're feeling adventurous, but at the very least you need some shell scripts to get a build out of SVN.
Making the transition
This is the big one. Announce the new regime to the developers. Get your boss to attend the meeting. Remind the developers to inform you of any changes they make to the database.
That night:
Take a full export with Data Pump
Drop all the application schemas.
Build the application from SVN
Reload the data - but not the data structures - with Data Pump
Hopefully you won't have any structural issues; but if the developer has made changes without telling you you'll know - and they won't have any data in the table.
Make sure you revoke the SYSDBA access as soon as possible.
The developers will need access to a set of schemas so they can write the ALTER scripts. In the developers don't have local personal databases or private schemas to test things I suggest you let them have access to that toy database to test change scripts. Alternatively you can let them keep the application owner access, because you'll be repeating the Trash'n'Rebuild exercise on a regular basis. Once they get used to the idea that they will lose any changes they don't tell you about they will knuckle down and start Doing The Right Thing.
Last word
Obviously this is a lot of vague windbaggery, lacking in solid detail. But that's politics for you.
Postscript
I was at a UKOUG event yesterday, and attended a session by a couple of smart chaps from Regdate. They have a product Source Control for Oracle which provides an interface between (say) SVN and the database. It takes a rather different approach from what I outlined above. But their approach is a sound one. Their tool automates a lot of things, and I think it might help you a lot in your current situation. I must stress that I haven't actually used this product but I think you should check it out - there's a 28 day free trial. Of course, if you don't have any money to spend then this won't help you.
you can find the desierd infos in the following trigger attributes
dictionary_obj_name
dictionary_obj_owner
ora_sysevent
here is the simple ON DATABASE trigger
CREATE OR REPLACE TRIGGER trigger_name
AFTER CREATE OR DROP ON DATABASE
BEGIN
IF dictionary_obj_type = 'TRIGGER'
THEN
INSERT INTO log_table ( trg_name, trg_owner, trg_action) VALUES (dictionary_obj_name,dictionary_obj_owner, ora_sysevent);
END IF;
END;
/
I'm looking for advice on how to best organize a new Oracle schema and dependent files in my project directory - with the sequences, triggers, DDL, etc. I've been using one monolothic file called schema.sql for some time, but I'm wondering if there's a best practice? Something like...
database/
tables/
person.sql
group.sql
sequences/
person.sequence
group.sequence
triggers/
new_person.trigger
Penny for your thoughts or a URL that I may have missed!
Thank you!
Storing DDL by object type is a reasonable approach-- anything is likely to be easier to navigate than a monolithic SQL script. Personally, though, I'd much rather have DDL organized by function. If you're building an accounting system, for example, you probably have a series of objects to manage accounts payable and a separate set of objects to manage accounts receivable along with some core objects for managing the general ledger accounts. That would lead to something along the lines of
database/
general_ledger/
tables/
packages/
sequences/
accounts_receivable/
tables/
packages/
sequences/
accounts_payable/
tables/
packages/
sequences
As the system gets more complex, that hierarchy would naturally get deeper over time. This sort of approach would more naturally mirror the way non-database code is stored in source control. You wouldn't have a single directory of Java classes in a directory structure like
middle_tier/
java/
Foo.java
Bar.java
You would organize the classes that implement the same sorts of business logic together and separate from the classes that implement different bits of business logic.
One item to consider is those SQLs which can act as 'latest only' scripts. These include CREATE OR REPLACE PROCEDURE/FUNCTION/TRIGGER etc. You run the latest version and you are not worried about what may have previously existed in the database.
On the other hand you have tables where you may start off with a CREATE TABLE followed by several ALTER TABLEs as changes to the schema evolve. And if you are doing an upgrade you may want to apply several of the ALTER TABLE scripts (preferably in order).
I'd argue against a 'functional grouping' unless it is really obvious where the lines are drawn. You probably don't want to be in a position where you have a USERS table in one group and a USER_AUTHORITIES in another and an AUTHORITY group in a third.
If you do have decent separation, then they are probably in separate schemas and you do want to keep schemas distinct (since you can have the same object names in different schemas).
The division-by-object-type arrangement, with the addition of a "schema" directory below the database directory works well for me.
I've worked with source control systems that have the additional division-by-function layer - if there are many objects it adds additional searching if you're trying to cross-reference the source control file with the object that you see in a database GUI navigator that generally groups objects by type. It's also not always clear how an object should be classified this way.
Consider adding a "grants" directory for the grants made by that schema to other schemas or roles, with one file per grantee. If you have "rule-based" grants such as "the APPLICATION_USER role always gets SELECT on all of schema X's tables", then write a PL/SQL anonymous block to perform this action. (You might be tempted to reverse-engineer the grants after they get put in place by some ad-hoc method, but it's easy to miss something when new tables or views are added to the application).
Standardize on a delimiter for all scripts and you'll make your life easier if you start deploying through a build utility such as Ant. Using "/" (vs. ";") works for both SQL statements as well as PL/SQL anonymous blocks.
In our projects we use somewhat combined approach: we have a core of our program as a root and other functionalities in subfolders:
root/
plugins/
auth/
mail/
report/
etc.
In all these folders we have both DDL and DML scripts almost all of them can be run more that once, e.g. all packages are defined as create or replace..., all data insertion scripts check whether data already exists and so on. This gives us the opportunity to rus almost all scripts without thinking that we can crash something.
Obviously this scenario can't be applied for create table and similar statements. For these scripts we have manually written small bash script that extracts specified files and runs them not failing on particular ORA errors, like: ORA-00955: name is already used by an existing object.
Also all files are mixed in the directories but differ with extensions: .seq goes for sequence, .tbl goes for table, .pkg goes for package interface, .bdy goes for package body, .trg goes for trigger an so on...
Also we have a naming convention denoting prefixes for all of our files: we can have cl_oper.tbl table with cl_oper.seq and cl_oper.trg sequence and triggers and cl_oper_processing.pkg together with cl_oper_processing.bdy with logic for mentioned objects. With this naming convention in file managers it's very easy to see all the files connected with some unit of logic for our project (whilst the grouping in directories by object types does not provide this).
Hope this information helps you somehow. Please leave comments if you have any questions.