I would like an explanation about the operation of the Express Edition database made available by Oracle for students, because I created a table by the terminal and did an insert and that's fine, I closed the application, when I opened and I made a query, the data was not more stored and the bank reported that there was nothing in the table in question.
Here are two questions:
Is your storage volatile, being used only so you can learn your commands?
Did you want an explanation of its use, and it also has a graphical interface?.
How does the Oracle Express Edition database work?
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asked by anonymous 28.11.2015 / 21:38
3 answers
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Oracle Express Edition is identical to enterprise editions, with only license and capacity limitations (base size, number of users, concurrent performance, etc.).
The problem you are experiencing is because Oracle's default behavior is implicitly initiate a transaction upon receiving a insert , delete , update ).
This transaction implicitly started needs to be explicitly terminated (with a commit or rollover command), otherwise Oracle will automatically > rollback at the end of the session (when you disconnect).
This behavior is not the default for all DBMSs . Microsoft SQL Server, for example, implicitly initiates and commits a transaction to each data manipulation command, as long as the user has not explicitly started the transaction (if the user initiates the transaction explicitly he also needs to commit explicitly).
So, to solve your problem, after inserting a record, execute the commit command, so the transaction will take effect and the log will be available to other users (other connections).
This default behavior can also be changed by server or session configuration, but is generally not a good idea.
The graphical interface is a separate database server tool, and there are several available, such as Oracle SQL Developer and SQuirreL SQL Client .
03.12.2015 / 20:18
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Try to run your command (table creation, insert, etc) and add to the end:
COMMIT;
Close the program and reopen it and make sure the data is still persisted, if you do, you have to enable the implicit commit in your database.
About your question about the Express version, the answer is no , this bank works the same as the paid version of the data store.
28.11.2015 / 23:49
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Understanding the behavior of a COMMIT
A transaction is usually initiated by an application or user. During execution of a transaction, data changes are generated and consequently changes in buffer (memory). This memory area is defined by the log_buffer parameter. When a user or application executes a COMMIT, Oracle immediately writes the data buffered (disk) to disk (redo log files) along with the redo data for the commit. While this process is not completely completed, (all data is recorded in Online Redo Log Files) Oracle will not "free" the session.
Changing the behavior of a COMMIT
You can change the behavior of a 2-way COMMIT statement:
Information taken from the link: link
29.11.2015 / 00:48