I have not found real sync from postgreSql to new graph database like neo4j, so I've decide to use same postgresql to sync one normalise tables with json table on the same postgresql with a differenta name for a database. So i have the best of two worlds, sql and nosql database.
When i see sql is more fast than graphql i can choose, and in the future, when i moved the nosql tables to a real graph database like neo4j and i ll be able to sync, i dont need to change the app that can use both database synced
Someone did already this? or it's a dumm idea? Or someone already use automatic libraries to sync from postgresql to neo4j ? and the another sens too ? or must I write sync scripts from scratch if i want to sync two databases?
Related
I have created a db long ago using django. Now as we are migrating the application, so I need all the CREATE TABLE sql queries which django might have run to create the entire db for our service (which has around 70-80 tables and each table has avg 30-70 columns).
Both the servers old and new are using Postgres for databases.
But the technology stack is completely different (A 3rd party proprietary application which will host the service) instead of django.
If I start to write all the tables again from scratch, it will take at least a week or two.
Is there any way either from Postgres or from django which can generate the CREATE TABLE sql schema for an entire db keeping all the relationship as is?
Also, I have to do minor modification to that schema as per customer requirement.
p.s - pg_dump won't work as I need actual schema itself to get it reviewed from client.
I'm trying to run a different database for development as my initial product release is coming so I'd like to know how to maintain two different databases. I'm using postgresql as my DBMS
I want development database and production database to have exactly the same schema. Is there a way to do this automatically? If I have to to manually, what would be the best way to update schema?
thank you
I want development database and production database to have exactly the same schema.
Then just create 2 databases with the same schema(s).
Or you can read more about template databases - https://www.postgresql.org/docs/11/manage-ag-templatedbs.html.
The idea is that when you create new database, it's actually copied from template1, thereof you can edit template1, and every new database will have schemas/tables that you need.
I have created custom script in Express that actually migrates SQL Server database to MongoDB.
But I am facing problems in live syncing between the two databases.
Currently I have added a column updated_by in both the databases.
Then I fetch the latest updated_by row from MongoDb and SQL Server database.
Then I check the date difference and based on it I update my MongoDB database.
There are lots of db tables and I am finding it difficult to identify that, which table is being updated.
Is there any log in SQL Server 2008 R2 that states which table is updated and at what time?
I need a mechanism like, any data update in the db table should immediately sync that rows into my MongoDB.
Any more suggestions on live data syncing is also welcome.
Thanks in advance. :)
When i have such requirement to Sync between Relational DB say (MYSQL) and Non-Relational DB (Mongodb).
I had followed following steps which may help others in future. and the concept is generally called as Change Data Capture
Capture changes (For MYSQL iam using triggers.)
Transform changes to a suitable changes
ie RDBMS to Non RDBMS
Update changes
Remember to sync the structural changes of database and corresponding implementaions.
Following links may help
https://www.flydata.com/blog/what-change-data-capture-cdc-is-and-why-its-important/
I have a large code base of an online charging application that is tightly coupled to Oracle and relies extensively on SQL queries , PL/SQL procedures etc.
In case , we are to migrate to a NO SQL based DB , would all the code need to be rewritten or are there some already available libraries/drivers that do the job of translation of sql queries to no-sql queries automatically by simply having us define a mapping between the current Oracle Schema and the new underlying NO-SQL DB schema (designed afresh)?
Thanks
You are going to rewrite a lot of things.
Relational database and nosql "things" are so different. And nosql are not transactional, eccept for documents.
You can save money going to mysql or postgresql (suggested) but still you have to implement a lot of things and you need to study proxy, connection pooling when you need to scale.
But, you can save a lot of work with Postgres plus advanced server of enterprise db: http://www.enterprisedb.com/products-services-training/products/postgres-plus-advanced-server
They say you can switch db without a single line to be changed. And save money.
Then you can access things like partitioning that will cost a lot in enterprise version of Oracle.
I am new to the PostgreSQL database. What my visual c++ application needs to do is to create multiple tables and add/retrieve data from them.
Each session of my application should create a new and distinct database. I can use the current date and time for a unique database name.
There should also be an option to delete all the databases.
I have worked out how to connect to a database, create tables, and add data to tables. I am not sure how to make a new database for each run or how to retrieve number and name of databases if user want to clear all databases.
Please help.
See the libpq examples in the documentation. The example program shows you how to list databases, and in general how to execute commands against the database. The example code there is trivial to adapt to creating and dropping databases.
Creating a database is a simple CREATE DATABASE SQL statement, same as any other libpq operation. You must connect to a temporary database (usually template1) to issue the CREATE DATABASE, then disconnect and make a new connection to the database you just created.
Rather than creating new databases, consider creating new schema instead. Much less hassle, since all you need to do is change the search_path or prefix your table references, you don't have to disconnect and reconnect to change schemas. See the documentation on schemas.
I question the wisdom of your design, though. It is rarely a good idea for applications to be creating and dropping databases (or tables, except temporary tables) as a normal part of their operation. Maybe if you elaborated on why you want to do this, we can come up with solutions that may be easier and/or perform better than your current approach.