What happens to existing tables during import using impdp - oracle

I want to export and import an entire schema from Prod to Dev, but Dev has already existing tables (that are not there in Prod) which I don't want to be affected.
So, the question is during import (impdp) what happens to those existing tables?
thanks.

if you have backuped full database including create database and create tables queries in backup then there occurs error.
To solve the problem you needs to remove each line that is intented to create database and new table.
if you have dumped data only data is added to existing table with no errors. (if contains no syntax error)
if You don't need data in dev database Then login to database server and delete all tables that are in prod and then import your database file.
if You don't want to delete data in dev database Then create entirely different database import file to that database and modify your connection string.

Related

Oracle DB Export does not preserve order or dependencies

I'm trying to export an Oracle DB using Oracle SQL Developer having tables, sequences, view, packages, etc. with dependencies on each other.
When I use Tools -> Database Export and select all DDL options, unfortunately the exported SQL file does not preserve the other that is some DB objects should be created before some other.
Is there a way to make the DB export utility preserve object dependencies/order? Or Is there any other tool do you use for this task?
Thank you
Normally expdp does a pretty good job. Problems arise when there are dependencies on objects/users that are not part of the dump. This is because the counter part, impdp, does not add grants on objects that are not created by impdp. I call that the 'not created by me syndrome' that impdp has.
If you have no external dependencies (external meaning to schema's that are not part of the dump), expdp/impdp do a good job for you. You might not be able to use it if you can not have access to the database server since expdp writes it's files on the database server.
If you happen to have access to a database server that is able to connect to the original database, you could pull the data over into your local database using a database link.

Oracle restore dmp to existing database

I wish to restore Oracle database from .dmp file.
When I try to import this file it doesn't replace current data.
The suggestion on forum is to drop user/schema and then import .dmp.
But I don't want to do it because everything is working under System user.
So if I drop system user i'll lose access to database management.
Any ideas how to import .dmp file and replace current data ?
If you are using datapump, I think you will have to consider parameter TABLE_EXISTS_ACTION
It seems you can use TABLE_EXISTS_ACTION=REPLACE to suits your need but be careful if there are SYSTEM tables in your dump file, better target the tables where you want to replace data using the TABLES=... clause.
P.S. This way you can refresh the tables and their data exactly, but unfortunately not possible to refresh the other existing objects such as functions, procedures, packages ... etc. without dropping and recreating them through datapump import.

Cloning a Oracle Database Schema

I have an Oracle 12c Instance with a scheme 'wadmin' user, this instance has tables, view, data, triggers, sequences etc.
For quick spinning of docker images, I need to clone the db schema as fast as possible , so that I can create another user 'wadmin1' link it to new docker and start my testing.
Any CLI/tools for the same, does oracle provide any options?
I do not know if this is exacly what you are looking for but you can export your Oracle schema using ORACLE DataPump tool. This involves storing exported schema in the Oracle directory. While exporting schema to file you can transform the schema name, omit unnecessary tables or data etc. Exported files with database schema can be later used for imported to new database instance. More information regarding Oracle DataPump you can find here. https://oracle-base.com/articles/10g/oracle-data-pump-10g#SchemaExpImp.
Alternatively you can have scripts that create the database stored in the Git repository and integrate your builds with too called Flyway https://flywaydb.org/ which can be used to automatize of database schema creation. This is also really convenient from source control point of view. All changes on the schema are pull requested.
In my team we use OracleDataPump when we want to recreate the database together with the data, Flyway is used as a part of our continues integration.

How to open the datapump file (External Table Oracle)?

I am going to unload the data from my table in Oracle DB to a file using oracle datapump. I am aware that I can import the file in to a different DB using datapump but would like to know if there is any other way to import or open the file?
i.e After the file is generated, I am going to send the file to my client who has no idea about Oracle DB etc. So is there any software or UI using which my client can open the file rather than using Oracle datapump to import (if no other go I will educate the client)? The reason I am going for external table etc because I have 50 million records that client wants to view.

how to import whole instance of oracle database to another instance with tablespaces and datefiles

when i am importing whole database instance to another database instance in oracle, only temp tables have been imported others table are not imported to the new instance, these tables are in user defined tablespace. Is there any solution for this problem?
You can use Database copy option in SQL Developer.

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