Technical Specifications

Development with eXtremeDB

Languages and programming interfaces

• Native (non-SQL) APIs are available for C/C++, Java, Scala, Python
• ODBC and JDBC drivers. C# can be used with the ODBC .NET Managed Provider.
• Rest API
• SQL-89 with extensions
  • SQL APIs are available for C/C++, Java, Python and Rust
  • Stored procedure languages are C/C++, Lua and Python

Learn more

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Supported Data Types

• Basic C/C++ language data types for C application
  • integers (short/long, signed/unsigned)
  • float (single -precision floating-point type as in C language)
  • double/long double (double-precision floating-point type as in C language)
  • char (signed/unsigned)
  • boolean (stores True or False)
  • structures
  • arrays
  • variable-length strings/VARBINARY/variable-length vectors
  • Most native data types for other programming languages : Python, Java, C#, Lua, and Rust
• Unicode character and wide-character data
  • nchar
  • wchar
• Database-specific
  • BLOBs
  • datetime
  • autoid and reference (stores system-generated unique object identifiers and references to unique identifiers)
  • OID (user-generated object identifier)
  • sequence (columnar storage for time series data)
  • nullable (allow the value to be set to the special value NULL)
  • default values
  • compact data layout (limits all internal class references to 16 bit; can meaningfully reduce storage space requirements for resource-constrained systems)

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Indexing

A database index is a data structure that improves the speed of data retrieval at the cost of additional writes and storage space to maintain it. Different index algorithms are used for different application scenarios.

• B-tree indexes are used for partial key (wildcard) search, pattern match (regex), ordered retrieval
• Hash indexes are available for in-memory tables/classes used only for equality comparisons)
• R-tree used for spacial access
• KD-tree is another space-partitioning data structure for organizing points in a k-dimensional space
• Patricia trie used mostly with IP addresses and telephone numbers
• Trigram used in text searches when the exact spelling of the target object is not known
• “Voluntary” index. B-tree or hash index support can be turned on/off on at runtime. When turn on the index is built & maintained by eXtremeDB until turned off
• User-defined indexes allow application-defined key compare functions, including custom hash functions

Watch a short Webinar segment about your index of choice. 

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Database Transactions

A transaction is a unit of work with the database (a single logical operation on the data). Transactions ensure ACID (Atomicity, Consistency, Isolation and Durability) properties and provide scheduling policies for multiple tasks accessing the database simultaneously. Transactions are implemented via transaction managers. eXtremeDB supports

• MURSIW transaction manager enforces Multiple Read/Single Write concurrent access to the database
• Exclusive transaction manager allows a single transaction at a time
• MVCC transaction manager stands for multi-versioning concurrency control, allows concurrent “readers” and “writers”
• Transaction priorities. Transaction managers schedule transactions based on application-specified priority levels (similar to RTOS task priorities)
• Several “delayed” transaction commit policies that “group” write transactions together to lower I/O overhead, trading higher performance for lower durability

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Debugging capabilities and monitoring

• The eXtremeDB debug-mode run-time includes numerous traps in the database code, for detection and easy remediation of programming errors
• For C/C++, the eXtremeDB-generated programming interface avoids void pointers and exploits the type-checking features of the compiler, with programmer mistakes generating a compile-time error
• eXtremeDB is available with source code, for complete control of the development environment
• Optional extended tracing ability
• Runtime diagnostic, performance monitoring and database configuration capabilities via graphical control panel

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Distributed architecture and remote access features

Distributed databases consist of multiple data repositories located in different sites either on the same network or on entirely different networks. The repositories can be stored in multiple physical locations and processing is distributed among multiple database nodes.

Distributed architectures

• High Availability implement Active master and Passive replica
• Cluster implements Multi-Master processing
• Active Replication Fabric supports bidirectional replication between IoT tiers and ability to queue replication during planned/unplanned loss of connection

Remote access

• Integrated web server and RESTful services support
• Integrated SSL support
• RemoteSQL

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