we have an Oracle DB that cannot take up any additional insert/update load. Is it possible to extract such commands from the .arc files and update another non-oracle DB so that I can run reports off the new DB? Once that is done, I can reduce the load of all queries and reports from the main DB!
I understand that it is these very .arc files that are used for replicating to another oracle DB and that is what I want to do - except that the target DB is not oracle.
Related
I made a custom application that is running from several years and is full of company data.
Now I need to replicate the application for another customer, so I set up a new server then i cloned the databases and empty all the tables.
Then I made a database and file shrink.
On the SQL Server side, the databases looks empty but if I run a grep search on the database files .mdf and .log I still can find recurrence of the previous company name also in system databases.
How do I really clean a SQL Server database?
Don't use backup/restore to clone a database for distribution to different clients. These commands copy data at the physical page/extent level, which may contain artifacts of deleted data, dropped objects, etc.
The best practice for this need is to create a new database with schema and system data from scratch using T-SQL scripts (ideally source controlled). If you don't already have these scripts, T-SQL scripts for schema/data can be generated from an existing database using the SMO API via .NET code or PowerShell. Here's the first answer I found with a search that uses the Microsoft.SqlServer.Management.SMO.Scripter class. Note you can include scripts data too (insert statements) by specifying the ScriptData scripting option for desired tables.
I would like to know the steps on how to restore data dumped from an Oracle database to a SQL Server database?
Our purpose is to get data from an external Oracle database out of our organization. Due to security concern, the team that manages data source refused us to transfer data through ODBC server link. They dumped the selected tables that we need so we can restore the data in our organization. Each table's data files include .sql file to create table and constraints, a ".ctl" file, one or multiple ".ldr" files.
An extra trouble is: one of the tables contains a blob column, which stores a lot of binary data files, such as PDF etc.. This column takes most of the size of our dumped files. Otherwise I could ask them to send us data in excel directly.
Can someone give me a suggestion about what route we should take?
Either get them to export the data in an open format, or load it into an Oracle instance you have full control over. .ctl and .ldr files looks like they used the old SQL*Loader.
I am trying to download my SQL Server database (that is more than 40 GB) from production server to my local machine. I need only schema & some of data as downloading 40 GB backup file & restoring is really tough task for me.
I have tried to use generate scripts to obtain schema, this was successful. But for getting data for (suppose approx. first 500 rows) of all tables, I am not sure how I should approach that.
Please let me know is there any other way to achieve this?
I am using Microsoft's SQL Server Version 12.0.xxx.
Thanks
SQL Server Management Studio provides a wizard which enables you to generate scripts not only for metadata (or schema) but also the scripts for data within database.
Please refer to Script Data in SQL Server
But if your database backup size is very big, the script file will be very huge.
Actually this wizard does not provide a parameter to script only for first 500 rows of each table.
Besides all, if you have foreign keys and constraints on your table definitions, you might not be enough to get only the first 500 rows. You need every referenced lookup data in your database in order to insert data into your transactional tables, or you need the parent for the child data.
This forces you to create a more smart script for data extraction.
I have an Oracle database and a SQL Server database. There is one table say Inventory which contains millions of rows in both database tables and it keeps growing.
I want to compare the Oracle table data with the SQL Server data to find out which records are missing in the SQL Server table on daily basis.
Which is best approach for this?
Create SSIS package.
Create Windows service.
I want to consume less resource to achieve this functionality which takes less time and less resource.
Eg : 18 millions records in oracle and 16/17 millions in SQL Server
This situation of two different database arise because two different application online and offline
EDIT : How about connecting SQL server from oracle through Oracle Gateway to SQL server to
1) Direct query to SQL server from Oracle to update missing record in SQL server for 1st time.
2) Create a trigger on Oracle which gets executed when record is deleted from Oracle and it insert deleted record in new oracle table.
3) Create SSIS package to map newly created oracle table with SQL server to update SQL server record.This way only few records have to process daily through SSIS.
What do you think of this approach ?
I would create an SSIS package and load the data from the Oracle table use a Data Flow / OLE DB Data Source. If you have SQL Enterprise, the Attunity Connectors are a bit faster.
Then I would load key from the SQL Server table into a Lookup transformation, where I would match the 2 sources on the key, and direct unmatched rows into a separate output.
Finally I would direct the unmatched rows output to a OLE DB Command, to update the SQL Server table.
This SSIS package will require a lot of memory, but as the matching is done in memory with minimal IO, it will probably outperform other solutions for speed. It will need enough free memory to cache all the keys from the SQL Server Table.
SSIS also has the advantage that it has lots of other transformation functions available if you need them later.
What you basically want to do is replication from Oracle to SQL Server.
You could do this in SSIS, A windows Service or indeed a multitude of platforms.
The real trick is using the correct design pattern.
There are two general design patterns
Snapshot Replication
You take all records from both systems and compare them somewhere (so far we have suggestions to compare in SSIS or compare on Oracle but not yet a suggestion to compare on SQL Server, although this is valid)
You are comparing 18 million records here so this is a lot of work
Differential replication
You record the changes in the publisher (i.e. Oracle) since the last replication then you apply those changes to the subscriber (i.e. SQL Server)
You can do this manually by implementing triggers and log tables on the Oracle side, then use a regular ETL process (SSIS, command line tools, text files, whatever), probably scheduled in SQL Agent to apply these to the SQL Server.
Or you could do this by using the out of the box replication capability to set up Oracle as a publisher and SQL as a subscriber: https://msdn.microsoft.com/en-us/library/ms151149(v=sql.105).aspx
You're going to have to try a few of these and see what works for you.
Given this objective:
I want to consume less resource to achieve this functionality which takes less time and less resource
transactional replication is far more efficient but complicated. For maintenance purposes, which platforms (.Net, SSIS, Python etc.) are you most comfortable with?
Other alternatives:
If you can use Oracle gateway for SQL Server then you do not need to transfer data and can make the query directly.
If you can't use Oracle gateway, you can use Pentaho data integration or another ETL tool to compare tables and get results. Is easy to use.
I think the best approach is using oracle gateway.Just follow the steps. I have similar type of experience.
Install and Configure Oracle Database Gateway for SQL Server.
https://docs.oracle.com/cd/B28359_01/gateways.111/b31042/installsql.htm
Now you can create a dblink from oracle to sql server.
Create a procedure which compare the missing records in oracle database and insert into sql server database.
For example, you can use this statement inside your procedure.
INSERT INTO "dbo"."sql_server_table"#dblink_name("column1","column2"...."column5")
VALUES
(
select column1,column2....column5 from oracle_table
minus
select "column1","column2"...."column5" from "dbo"."sql_server_table"#dblink_name
)
Create a scheduler which execute the procedure daily.
When both databases are online, missing records will be inserted to sql server. Otherwise the scheduler fail or you can execute the procedure manually.
It takes minimum resource.
I will suggest having a homemade ETL solution.
Schedule an oracle job to export source table data (on a daily
manner based on the application logic ) to plain CSV format.
Schedule a SQL-Server job (with acceptable delay from first oracle job) to read this CSV file and import it
to a medium table inside sql-servter using BULK INSERT.
Last part of the SQL-Server job will be reading medium table data
and do the logic(insert, update target table). I suggest having another table to store reports of this daily job result.
If we have the same database schema in a database on Postgresql and SQL Server (table, primary keys, indexes and triggers are the same) what would be the best way to move data from one database to another? Currently we have one in-house .NET program that does the following through two ODBC connections:
read a row from source database table 1
construct an insert statement
write a row into destination database table 1
Go to 1 if there are more rows in the table
Move to next table in database and go to 1
Needless to say: this is a very slow process and I would be interested if there was a better/faster solution to this?
If it's a "one off" migration, there's a tool you get with SQL Server which allows you to move data around between databases (I'm not on a Windows machine right now, so can't tell you what it's called - something like import/export tool).
If it's an ongoing synchronisation, you can look at the MS Sync framework, which plays nice with SQL Server and Postgres.
The answer is bulk export and bulk loading. You can go much faster by using the copy command in PostgreSQL https://www.postgresql.org/docs/current/static/sql-copy.html to dump data from the tables in the CSV format and then use the bulk insert in SQLServer Import CSV file into SQL Server. A rule of thumb is to harness parallelism for the process. Check if you can load the data ins CSV in parallel to SQL Server and if you have many tables then you can also have a parallelism on the level of separate tables. By the way, loading or migrating data row by row is one of the slowest ways.