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- @ManyToOne - object references.
- @OneToMany - collections.
- @MappedSuperClass - Useful
timestamping class and for a common
- @Lob - stores lobs in S3 so make it as
big as you want (up to 5GB).
- @Id - Assigns UUID automatically
- Lazy loading on ManyToOne, Lobs and
OneToMany so only hits SDB on an as
- Rudimentary caching to reduce hits on
- JPA Queries
- Perst All-Java Embedded Database
Adds KD-Tree Indexes
McObject provides support for the KD-Tree. A
KD-Tree is a database index that is used in
spatial and pattern-matching applications, to
Perst. It is an open source, object-oriented all-
Java embedded database system. Developers
who have been working with Perst, the KDTree
helps them in expanding coding efficiency
and helps in making Java data objects easier to
use in certain types of application.
The new k-dimensional tree or in short KD-Tree
index enables us to add a structure in Perst for
storing and manipulating point objects in a kdimensional
space by partitioning that space.
These are practically used in computer graphics,
geographical information systems and biometric
applications like fingerprint matching as well as
their efficiency in handling multi-dimensional
data, KD-trees helps the developers in "normal"
applications where query predicates include
different combinations of object fields.
McObject's Perst embedded database and eXtremeDB embedded database provides a collection various index types, including:
- B-trees used in common sorting, searching, insertions, and deletions
- R-trees used for geospatial indexing (mainly in GPS/navigation systems)
- T-trees used in all-in-memory data storage and accessHash tables for quickly locating a single unique index
- Patricia trie index, that is used for
speedly searching in networking and
- Custom indexes used in b-trees
allowing to the application to define
the collating sequence of entries; it is
also useful in implementing soundex
algorithm searches, for example
- Bit or bitmap used for optimizing the
indexes for columns in which values
- TimeSeries class used in dealing
efficiently with small fixed-size objects
- Specialized versions of collections used
in thick indices (indexes having
multiple duplicate values), and bit
- KD-Tree is developed by using the
latest versions of Perst for Java and
.NET. It is available for free download
at McObject’s Web site.
Mar 2008 | Java Jazz Up | 11
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