I have few tables in my database where the primary keys are auto generated using Hibernate seqhilo generator configuration. We need to archive these records and at a later point, should be able to restore them in case of a business scenario. My question is if I restore these tables with simple insert statements will that suffice or should I worry about the sequence generator? I would like to have the same ID and not a new generated one. To be clear these re-inserts will happen via direct SQL and not via Hibernate.
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I am trying to develop some scripts so I can recreate the oracle schema for a development user when I need to refresh the data from a MySQL production database.
I am using the dbms_metadata.get_ddl function to generate the ddl, but it also creates all the constraints for the tables and I need to wait on creating at least the foreign constraints since I want to load the actual data first.
Is there a way to tell dbms_metadata.get_ddl to not create the indexes and constraints?
We have a legacy app that I am rewriting in .net. All of our databases are oracle and make use of database links. Is there any way for Entity Framework 6 to generate models based on tables located on a different database?
Currently the legacy app gets data from table like this
SELECT * FROM emp#foo2;
where its db connection is to database foo that has a database link to the database foo2.
I would like to reproduce this using EF6. So far all I have found regarding this is this question.
You can do two things that EF 4 or higher will work with:
CREATE VIEW EMP as SELECT * FROM emp#foo2;
CREATE MATERIALIZED VIEW EMP as SELECT * FROM emp#foo2;
LOBS are not accessible across a database link without some contorted PL/SQL processing to read the LOB piece by piece.
I believe fast refresh does not work across database links so you must consider the size of the table on the linked database. If you are refreshing a million rows you may find the time to do this is an issue. Most large tables are full of tombstone data that never changes so a timestamp column with the last modified date could help you create a package that only picks out the changed data.
If you are doing complicated joins for either ensure that Oracle considers the column that would be the primary key as not null.
You can add a primary key on views and materialized view but it must be disabled. See here for details.
I need to do an Oracle data migration from 11g to 12c where schema changes are abundant. I have an excel sheet which describes all the schema changes. Excel sheet has the columns for 'old_table_name', 'old_column_name', 'old_value' and same for the new tables. Some values can be directly copied to the new table and some cannot be done that way.
For example I have to transform the old column value when it is moved to the new table. Some transformation are complex and they cannot be simply mapped. They should be transformed by joining with other tables in the old database. I was trying the Talend Open Studio Data Integration tool for this and found it is a bit complex to go ahead with that tool in my case. Does anyone have an idea of getting this done using Talend or any other tool? What is the ideal approach when doing a migration like this? I have included a sample of the excel sheet below which only has simple transformations.
The kind of converions shown in the spreadsheet can all be performed on the table itself using rename statements and/or basic ddl and dml statements. I would load the old table into the new database and perform these statement on the table.
alter table
old_table_one
rename to
new_table_one;
alter table
new_table_one
rename column
old_col_one
to
new_col_one;
update new_table_one
set new_col_one = 'A_NEW'
where new_col_one = 'A';
etc.
I've database with 15 tables. Now due to development process one column has to added to all the tables in the database. This changes should not affect the existing process because some other services are also consuming this database. So to accomplish it I thought of creating a new database. Is there are any other way to do it.
Usually it should be enough to create a new schema ("user") and create the tables in that new schema. In Oracle, identically named tables can exist in several schemas.
CREATE USER xxx IDENTIFIED BY yyy
you can create another schema for development and import the table to new schema.Developer should use the development schema instead of production schema.you can also create new database and import from current database but it might be last option
What's wrong with alter table T add (COL varchar2(5)); ?
Of course dependend stored procedures or packages become invalid.
You can leave them alone, then the first call would return an exception and auto-recompile the called procedure. Or you can alter procedure P compile;.
I have several externally supplied tables which I can't modify. In my case these are things like the built in Oracle tables.
What I have is several entities which map on to these tables, but when I do my DDL generation I don't want them to be generated. Is there an annotation or an attribute I can set to ignore certain entities in the DDL generation?
You could simply switch to "create" ddl from "drop-create". The "create" calls for the existing tables would be ignored. Unfortunately there is currently no option in EclipseLink to prevent a table from being dropped when using "drop-create". Your best option is to have EclipseLink write the DDL to file and remove the lines for tables you do not want altered. It is likely that something similar will be available in a future version of EclipseLink. You can monitor and provide feedback on the currently active "extensions" feature in EclipseLink : http://wiki.eclipse.org/EclipseLink/Development/2.4.0 . Monitor this page for more information.