Compare data of table from two different Database - oracle

I have two separate database in two separate servers. Both these database have same table . I just wanted to compare similar tables wrt to the data contained.
Also to access one database from other database do I need to create a DBLink

Have you tried to find anything in Google? There are millions of posts for this topic.
Use this documentation to learn about dbms_comparison package

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oracle schema sharing , is it possible?

Trying to understand if there is any such concept like this in Oracle Database.
Let's say I have two Databases, Database_A & Database_B
Database_A has schema_A, is there a way I can attach this schema to Database_B?
What I mean by this is if there is a job populating a TABLE_A in schema_A, I can see that read-only view in Database_B. We are trying to split a big Oracle database into two smaller databases and have a vast PL/SQL code, and trying to minimize the refactoring here.
Sharding might be what you're looking for. The schemas and tables will still logically exist on all databases, but you can arrange the data to be physically stored in specific databases. There might be a way to setup shardspaces, tablespaces, and user default tablespaces in a way where each schema's data is automatically stored in a specific database.
But I haven't actually used sharding. From what I've read, it seems to be designed for massive distributed OLTP systems, and it is likely complicated to administer. I'd guess this feature isn't worth the hassle unless you have petabytes of data.

ORACLE HCM table relationship

where can I find the table relationship for Oracle HCM tables? Does it even exist? I can't find anything related to it.
Thanks.
Please refer the below link. Don't forget to change 22b to 22c and to 22d then 23a for regular quarterly updates.
https://docs.oracle.com/en/cloud/saas/human-resources/22b/oedmh/index.html
This guide contains the information about tables within Oracle HCM Cloud and their columns, primary keys, and indexes. The guide also includes the information about views within Oracle HCM Cloud along with the columns and queries associated with each view.

Synchronize two Oracle databases

I have two oracle databases. Database A and Database B. Database B should be in sync with Database A. Data within DB- B wont be altered, it is only for view purpose. All the data change in DB- A should reflect in DB- B. After googling, I found db link and Materialized view
could help but I am not clear how to use them. Please give any idea.
I think you need to read the following:
http://docs.oracle.com/cd/B19306_01/backup.102/b14191/rcmdupdb.htm
http://docs.oracle.com/cd/E11882_01/server.112/e22490/dp_overview.htm#SUTIL100
A materialized view can be used for replication purposes but what you are referring to is duplication not replication.
If you all have a DBA in your org most definitely hand this task over to them. These are the kind of problems they eat for breakfast.
Best of luck.

Oracle copy data between databases honoring relationships

I have a question regarding the oracle copy command:
Is it possible to copy data between databases (were the structure is the same) and honor relationships in one go without(!) writing procedures?
To be more precise:
Table B refers (by B.FK) to table A (A.PK) by a foreign key (B.FK -> A.PK; no relationship information is stored in the db itself). The keys are generated by a sequence, which is used to create the PK for all tables.
So how to copy table A and B while keeping the relationship intact and use the target DBs sequence to generate new primary keys for the copied data (i cannot use the "original" PK values as they might already be used in the same table for a different dataset)?
I doubt that the copy command is capable to handle this situation but what is the way to achieve the desired behavior?
Thanks
Matthias
Oracle has several different ways of moving data from one database to another, of which the SQL*Plus copy command is the most basic and the least satisfactory. Writing your own replication routine (as #OldProgrammer suggests) isn't much better.
You're using 11g, so move into the 21st century by using the built-in Streams functionality.
There is no way to synchronize sequences across databases. There is a workaround, which is explained by the inestimable Tom Kyte.
I generally prefer db links and then use sql insert statements to copy over data.
In your scenario , first insert data of Table A using DB link and then table. If you try otherway round, you will error.
For info on DB link , you canc heck this link: http://docs.oracle.com/cd/B28359_01/server.111/b28310/ds_concepts002.htm

working with LINQ to Entities against multiple sql server databases

I'm building a project combined of number of sites with common subject.
The sites rely on one central database that holds the common info for all of them.
In addition, each site has another database that holds its unique info (I will refer to it as unique-db in the next lines so I won't be misunderstood).
For example, the Languages table sits in the central db. That said, I suddenly noticed that I need to use the Languages table in one of my unique-db in order for the table to act as a FK so I don't have to create the same table again in the unique-db.
Do I have to create the same table again this time in the unique-db? Or is there a way to connect tables from separate databases?
In addition, we decided using linq2entity and soon we're gonna run some complex queries against the different databases. Will I have a problem with this matter?
How should I go on with that? Was it wise to split the data into a few databases?
I really appreciate all the help I can get!
One thing that might make your life easier is to create views of the central tables in each unique db. Linq to Entities will pick up views as if they were tables.

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