My team and I are rapidly developing an Webapp backed by an Oracle DB. We use maven's plugin flyway to manage our db creation and population from INSERT SQL scripts. Typically we add 3-4 tables per sprint and / or modify the existing tables structure.
We model the schema in an external tool that generates the schema including the constraints and run this in first followed by the SQL INSERTs to ensure the integrity of all the data.
We spend too much time managing the changes to the SQL to cover the new tables - by this I mean adding the extra column data to the existing SQL INSERT statements not to mention the manual creation of the new SQL INSERT data particularly when they reference a foreign key.
Surely there is another way, maybe maintaining raw data in Excel and passing this through a parser to the DB. Has anyone any ideas?
10 tables so far and up to 1000 SQL statements, DB is not live so we tear it down on every build.
Thanks
Edit: The inserted data is static reference data the platform depends on to function - menus etc.
The architecture is Tomcat, JSF, Spring, JPA, Oracle
Please store your raw data in tables in the database - hey! why on earth do you want to use Excel for this? You have Oracle Database - the best tool for the job!
Load your unpolished data using SQL*Loader or external tables into regular tables in the database.
From there you have SQL - the most powerful rdbms tool to manipulate your data.
NEVER do slow by slow inserts. (1000 sql statements). Please do CTAS.
Add/enable the constraints AFTER you have loaded all the data.
create table t as select * from raw_data;
or
insert into t (x,y,z) select x,y,z from raw_data;
Using this method, you can bypass the SQL engine and do direct inserts (direct path load). This can even be done in parallel to make your data go into the database superfast!
Do all of your data manipulation in SQL or PLSQL. (Not in the application)
Please invest time learning the Oracle Database. It is full of features for you to use!
Don't just use it like a datadump (a place where you store your data). Create packages - interfaces to your application - your API to the database.
Don't just throw around thousands of statements compiled into your application. It will get messy.
Build your business logic inside the database PLSQL - use your application for presentation.
Best of luck!
Alternatively, you also have the option to implement a Java migration. It could read whatever input data you have (Excel, csv, ...) and do the proper inserts.
Related
I am new to SQL server. Database: SQL Server 2012, Size 2TB
We are planning to consolidate multiple databases.dbo.* objects under a single database as different schemas (databaseN.SchemaN.). Thus we need to prepare scripts to move database1.dbo. objects in another database as a different schema (e.g. database2.schema2.*) including all the dependent objects (need exact replica). This needs to be done without using any tools (SSMS, ApexSQL etc).
How should I go about scripting this. I was thinking on the lines of below approach:
Extract complete metadata (including all constraints/triggers/indexes/keys/partitions etc)
Extract data
Execute metadata scripts on target
disable all relational constraints and triggers
insert all the extracted data
enable all the relational constraints and triggers.
If this approach is fine, can I get some assistance in how to go about scripting this. Also, please suggest if any other approach. Some tables are partitioned and 50-100GB in size.
We have and old database with a poorly thought out table structure, virtually no relationships setup and no naming schemes. I've created a new database with a clean relational data structure that implements proper design practices.
I'm looking for advice on different methods to migrate the old data over to the new format. This will require a lot of data re-shaping which won't be fun. The data is heavily accessed and the challenge will be to keep both databases in sync for all relevant data (accounts, important services etc).
I thought triggers might be the way to go here - but maybe there is a different method that I am unaware of (maybe MS Sync Framework, or a code-level data adapter which will be more work because there is so much data access code spread all over the place, classic ASP and .Net over dozens of projects). The database in question is SQL Server 2005, running in SQL Server 2000 compatibility mode.
I think the way to go is to write a stored procedure in the new database, which will actually pull your delta changes (only the modifications that were done from the last run to the instant the stored proc is run), and put this stored procedure in the sql agent job.
Configure the sql agent job to run for every 15 minutes and let the data sync in.
disadvantages of using triggers in this scenario
triggers will reduce the performance, as the sql server will execute the trigger code as well along with the update/ insert /delete statements and includes these as part of the execution at every time, i.e. if your trigger code takes 2 seconds to execute and the update statement with no trigger takes 2 seconds to execute, then the update time will be increased to 4 seconds with trigger in place. So employing triggers in this case might result in huge performance bottle neck.
I'm dealing with the same situation at my work, and I'm currently writing an application to do the migration. The original database has no established relationships, so it's really like a set of disconnected spreadsheets. By building my own application, I'm able to migrate the data using newly-established foreign keys, and assign data-specific defaults in place of nulls.
I was wondering what are the best practices in order to write SQL scripts to set up databases for production and/or development, for instance:
Should I include the CREATE DATABASE statement?
Should I create users for the database in the same script?
Is correct to disable FK check before executing the body of the script?
May I include the hole script in a transaction?
Is better to generate 1 script per database than one script for all of them?
Thanks!
The problem with your question is is hard to answer as it depends on the way the scripts are used in what you are trying to achieve. you also don't say which DB server you are using as there are tools provided which can make some tasks easier.
Taking your points in order, here are some suggestions, which will probably be very different to everyone elses :)
Should I include the CREATE DATABASE
statement?
What alternative are you thinking of using? If your question is should you put the CREATE DATABASE statement in the same script as the table creation it depends. When developing DB I use a separate create DB script as I have a script to drop all objects and so I don't need to create the database again.
Should I create users for the database in the same script?
I wouldn't, simply because the users may well change but your schema has not. Might as well manage those changes in a smaller script.
Is correct to disable FK check before executing the body of the script?
If you are importing the data in an attempt to recover the database then you may well have to if you are using auto increment IDs and want to keep the same values. Also you may end up importing the tables "out of order" an not want checks performed.
May I include the whole script in a transaction?
Yes, you can, but again it depends on the type of script you are running. If you are importing data after rebuilding a db then the whole import should work or fail. However, your transaction file is going to be huge during the import.
Is better to generate 1 script per database than one script for all of them?
Again, for maintenance purposes it's probably better to keep them separate.
This probably depends what kind of database and how it is used and deployed. I am developing a n-tier standard application that is deployed at many different customer sites.
I do not add a CREATE DATABASE statement in the script. Creating the the database is a part of the installation script which allows the user to choose server, database name and collation
I have no knowledge about the users at my customers sites so I don't add create users statements also the only user that needs access to the database is the user executing the middle tire application.
I do not disable FK checks. I need them to protect the consistency of the database, even if it is I who wrote the body scripts. I use FK to capture my errors.
I do not include the entire script in one transaction. I require from the users to take a backup of the db before they run any db upgrade scripts. For creating of a new database there is nothing to protect so running in a transaction is unnecessary. For upgrades there are sometimes extensive changes to the db. A couple of years ago we switched from varchar to nvarchar in about 250 tables. Not something you would like to do in one transaction.
I would recommend you to generate one script per database and version control the scripts separately.
Direct answers, please ask if you need to expand on any point
* Should I include the CREATE DATABASE statement?
Normally I would include it since you are creating and owning the database.
* Should I create users for the database in the same script?
This is also a good idea, especially if your application uses specific users.
* Is correct to disable FK check before executing the body of the script?
If the script includes data population, then it helps to disable it so that the order is not too important, otherwise you can get into complex scripts to insert (without fk link), create fk record, update fk column.
* May I include the hole script in a transaction?
This is normally not a good idea. Especially if data population is included as the transaction can become quite unwieldy large. Since you are creating the database, just drop it and start again if something goes awry.
* Is better to generate 1 script per database than one script for all of them?
One per database is my recommendation so that they are isolated and easier to troubleshoot if the need arises.
For development purposes it's a good idea to create one script per database object (one script for each table, stored procedure, etc). If you check them into your source control system that way then developers can check out individual objects and you can easily keep track of versions and know what changed and when.
When you deploy you may want to combine the changes for each release into one single script. Tools like Red Gate SQL compare or Visual Studio Team System will help you do that.
Should I include the CREATE DATABASE statement?
Should I create users for the database in the same script?
That depends on your DBMS and your customer.
In an Oracle environment you will probably never be allowed to do such a thing (mainly because in the Oracle world a "database" is something completely different than e.g. in the PostgreSQL or MySQL world).
Sometimes the customer will have a DBA that won't let you create databases (or schemas or users - depending on the DBMS in use). So you will need to supply that information to the DBA in order for him/her to prepare the environment for your script.
May I include the hole script in a transaction?
That totally depends on the DBMS that you are using.
Some DBMS don't support transactional DDL and will implicitely commit any transaction when you execute a DDL statement, so you need to consider the order of your installation script.
For populating the tables with data I would definitely try to do that in a single transaction, but again this depends on your DBMS.
Some DBMS are faster if you commit only once or very seldomly (Oracle and PostgreSQL fall into this category) but will slow down if you commit more often.
Other DBMS handle smaller but more transactions better and will slow down if the transactions get too big (SQL Server and MySQL tend to fall into that direction)
The best practices will differ considerably on whether it is the first time set-up or a new version being pushed. For the first time set-up yes you need create database and create table scripts. For a new version, you need to script only the changes from the previous version, so no create database and no create table unless it is a new table. Now you need alter table statements becasue you don't want to lose the existing data. I do usually write stored procs, functions and views with a drop and create statment as dropping those pbjects doesn't generally affect the underlying data.
I find it best to create all database changes with scripts that are stored in source control under the version. So if a client is new, you run the create version 1.0 scripts, then apply all the other versions in order. If a client is just upgrading from version 1.2 to version 1.3, then you run just the scripts in version 1.3 source control repository. This would also include scripts to populate or add records to lookup tables.
For transactions you may want to break them up into several chunks not to leave a prod database locked in one transaction.
We also write reversal scripts to return to the old version if need be. This makes life easier if you have a part of a change that causes unanticipated problems on prod (usually performance issues).
Firstly, let me apologize for the title, as it probably isn't as clear as I think it is.
What I'm looking for is a way to keep sample data in a database (SQL, 2005 2008 and Express) that get modified every so often. At present I have a handful of scripts to populate the database with a specific set of data, but every time the database is changed all the scripts have to be more or less rewritten and I was looking for some alternatives.
I've seen a number of tools and other software for creating sample data in a database, some free and some not. Are there any other methods I haven’t considered?
Thanks in advance for any input.
Edit: Also, if anyone has any advice at all in dealing with keeping data in sync with a changing application or database, that would be of some help as well.
If you are looking for tools for SQL server, go visit Red Gate Software, they have the best tools. They have a data compare tool that you can use to keep lookup type tables up-to-date and a SQL compare tool that you can use to keep the tables synched up between two datbases. So using SQL data compare, create a datbase with all the sample data you want. Then periodically refresh your testing db (or your prod db if these are strictly lookup type tables) using the compare tool.
I also like the alternative of having a script (you can use Red Gate's tool to create scripts) because that means you can store this info in your source control and use it as part of a deployment package to other servers.
You could save them in another database or the same db in different tables distinguished by the name, like employee_test
Joseph,
Do you need to keep just the data in sync, or the schema as well?
One solution to the data question would be SQL Server snapshots. You create a snapshot of your initial configuration, so any changes to the "real" database don't show up in the snapshot. Then, when you need to reset the table, select from the snapshot into a new table. I'm not sure how it will work if the schema changes, but it might be worth a try.
For generation of sample data, the Database project in Visual Studio has functionality that will create fake/random data.
Let me know if this make sense.
Erick
I am writing code to migrate data from our live Access database to a new Sql Server database which has a different schema with a reorganized structure. This Sql Server database will be used with a new version of our application in development.
I've been writing migrating code in C# that calls Sql Server and Access and transforms the data as required. I migrated for the first time a table which has entries related to new entries of another table that I have not updated recently, and that caused an error because the record in the corresponding table in SQL Server could not be found
So, my SqlServer productions table has data only up to 1/14/09, and I'm continuing to migrate more tables from Access. So I want to write an update method that can figure out what the new stuff is in Access that hasn't been reflected in Sql Server.
My current idea is to write a query on the SQL side which does SELECT Max(RunDate) FROM ProductionRuns, to give me the latest date in that field in the table. On the Access side, I would write a query that does SELECT * FROM ProductionRuns WHERE RunDate > ?, where the parameter is that max date found in SQL Server, and perform my translation step in code, and then insert the new data in Sql Server.
What I'm wondering is, do I have the syntax right for getting the latest date in that Sql Server table? And is there a better way to do this kind of migration of a live database?
Edit: What I've done is make a copy of the current live database. Which I can then migrate without worrying about changes, then use that to test during development, and then I can migrate the latest data whenever the new database and application go live.
I personally would divide the process into two steps.
I would create an exact copy of Access DB in SQLServer and copy all the data
Copy the data from this temporary SQLServer DB to your destination database
In that way you can write set of SQL code to accomplish second step task
Alternatively use SSIS
Generally when you convert data to a new database that will take it's place in porduction, you shut out all users of the database for a period of time, run the migration and turn on the new database. This ensures no changes to the data are made while doing the conversion. Of course I never would have done this using c# either. Data migration is a database task and should have been done in SSIS (or DTS if you have an older version of SQL Server).
If the databse you are converting to is just in development, I would create a backup of the Access database and load the data from there to test the data loading process and to get the data in so you can do the application development. Then when it is time to do the real load, you just close down the real database to users and use it to load from. If you are trying to keep both in synch wile you develop, well I wouldn't do that but if you must, make a nightly backup of the file and load first thing in the morning using your process.
You may want to look at investing in a tool like SQL Data Compare.
I believe it has support for access databases too, and you can download a trial.
I you are happy with you C# code, but it fails because of the constraints in your destination database you temporarily can disable them and then enable after you copy the whole lot.
I am assuming that your destination database is brand new DB with no data, and not used by anyone when the transfer happens
It sounds like you have two problems:
You're migrating data from one database to another.
You're changing your schema.
Doing either of these things is tricky if you are trying to migrate the data while people are using the data.
The simplest approach is to migrate the data based on a static copy of the data, and also to queue updates to that data from the moment you captured the static copy. I don't know how easy this is in Access, but in SQLServer or Oracle you can use the redo logs for this or a manual solution using triggers. The poor-man's way of doing this is to make triggers for all the relevant tables that log the primary key of the records that have changed. Then after the old database is shut off you can iterate over those keys and get those records from the old database and put them into the new database. Just copy the whole record; if the record was deleted then delete it from the new database.
Your problem is compounded by the fact that you can't simply copy the data, you have to transform it. This means you probably have to shut down both databases and re-migrate the records based on the change list. It will take a lot of planning to ensure you get things right and I'd recommend writing a testing script that can validate that the resulting data is correct.
Also I'd ensure that the code for the migration runs inside one of the databases if possible. Otherwise you are copying the data twice and this will significantly harm the performance.