UnQLite is a in-process software library which implements a self-contained, serverless, zero-configuration, transactional NoSQL database engine. UnQLite is a document store database similar to MongoDB, Redis, CouchDB etc. as well a standard Key/Value store similar to BerkeleyDB, LevelDB, etc.

UnQLite is an embedded NoSQL (Key/Value store and Document-store) database engine. Unlike most other NoSQL databases, UnQLite does not have a separate server process. UnQLite reads and writes directly to ordinary disk files. A complete database with multiple collections, is contained in a single disk file. The database file format is cross-platform, you can freely copy a database between 32-bit and 64-bit systems or between big-endian and little-endian architectures. UnQLite features includes:

• Serverless, NoSQL database engine.
• Transactional (ACID) database.
• Zero configuration.
• Single database file, does not use temporary files.
• Cross-platform file format.
• UnQLite is a Self-Contained C library without dependency.
• Standard Key/Value store.
• Document store (JSON) database via Jx9.
• Support cursors for linear records traversal.
• Pluggable run-time interchangeable storage engine.
• Support for on-disk as well in-memory databases.
• Built with a powerful disk storage engine which support O(1) lookup.
• Thread safe and full reentrant.
• Simple, Clean and easy to use API.
• Support Terabyte sized databases.
• BSD licensed product.
• Amalgamation: All C source code for UnQLite and Jx9 are combined into a single source file.
• Highly available online support.

SQL::Translator is a group of Perl modules that manipulate structured data definitions (mostly database schemas) in interesting ways, such as converting among different dialects of CREATE syntax (e.g., MySQL-to-Oracle), visualizations of schemas (pseudo-ER diagrams: GraphViz or GD), automatic code generation (using Class::DBI), converting non-RDBMS files to SQL schemas (xSV text files, Excel spreadsheets), serializing parsed schemas (via Storable, YAML and XML), creating documentation (HTML and POD), and more. New to version 0.03 is the ability to talk directly to a database through DBI to query for the structures of several databases.

Through the separation of the code into parsers and producers with an object model in between, it's possible to combine any parser with any producer, to plug in custom parsers or producers, or to manipulate the parsed data via the built-in object model. Presently only the definition parts of SQL are handled (CREATE, ALTER), not the manipulation of data (INSERT, UPDATE, DELETE).

You can select the collection via:

mongodump -d some_database -c some_collection

[Optionally, zip the dump (zip some_database.zip some_database/* -r) and scp it elsewhere]

Then restore it:

mongorestore -d some_other_db -c some_or_other_collection dump/some_collection.bson

Existing data in some_or_other_collection will be preserved. That way you can "append" a collection from one database to another.

Prior to version 2.4.3, you will also need to add back your indexes after you copy over your data. Starting with 2.4.3, this process is automatic, and you can disable it with --noIndexRestore.

The GUI for MongoDB. Visually explore your data. Run ad hoc queries in seconds. Interact with your data with full CRUD functionality. View and optimize your query performance. Available on Linux, Mac, or Windows. Compass empowers you to make smarter decisions about indexing, document validation, and more.

As with everything that contains valuable data, PostgreSQL databases should be backed up regularly. While the procedure is essentially simple, it is important to have a basic understanding of the underlying techniques and assumptions.

Most options can be set using their actual names in the my.cnf.