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Geospatial functions

given latitude/longitude) ?Normally you would calculate the distance like: double cx = Math.toRadians(fromLat); double cy = Math.toRadians(fromLon); double px = Math.toRadians(toLat); double py = Math.toRadians(toLon); // see http://de.wikipedia.org/wiki/Orthodrome double gamma = Math.acos

CRUD Database Operations with JPA

a Double object reflecting the average x value of all the Point objects in the database. Retrieving

Entity Management Settings

than double cascade) is sufficient. The <dirty-tracking> element <dirty-tracking arrays="false


.0 Expression<Double> avg( Expression<N> x) Create an aggregate expression applying the avg operation ... Expression<Double> sqrt( Expression<?> x) Create an expression that returns the square root of its argument ... - expression y - expression Returns: sum Since: JPA 2.0 Expression<Double> sumAsDouble( Expression


Method javax.persistence.criteria.CriteriaBuilder Expression<Double> sumAsDouble( Expression<Float> x ) Create an aggregate expression applying the sum operation to a Float-valued expression, returning a Double result. Parameters: x - expression representing input value to sum operation Returns: sum expression Since: JPA 2.0


Method javax.persistence.criteria.CriteriaBuilder Expression<Double> toDouble( Expression<?> number ) Typecast. Returns same expression object. Parameters: number - numeric expression Returns: Expression<Double> Since: JPA 2.0

Step 2: Entity Class and Persistence Unit

the persistence.xml file in a text editor (by right clicking and selecting Edit or by double click


Returns: the new value for the field Since: JDO 1.0 double getDoubleField( PersistenceCapable pc, int field, double currentValue) Return the value for the field. Return the value for the field. Parameters ... ( PersistenceCapable pc, int field, double currentValue) The value of the field requested to be provided

setDoubleField(pc, field, currentValue, newValue)

Method javax.jdo.spi.StateManager void setDoubleField( PersistenceCapable pc, int field, double currentValue, double newValue ) Mark the field as modified by the user. Parameters: pc - the calling PersistenceCapable instance field - the field number currentValue - the current value of the field


to be stored into the ObjectId. Since: JDO 1.0 double fetchDoubleField(int fieldNumber) Fetch one field ... of the field from the ObjectId. Since: JDO 1.0 void storeDoubleField(int fieldNumber, double value) Store

Getting Started

ObjectDB is very easy to use. Follow the Getting Started Tutorial and the Quick Tour manual chapter and in minutes you may be able to write and run first Java programs against ObjectDB.

Prior knowledge or experience in database programming (SQL, JDBC, ORM, JPA, etc.) is not required, but some background in using the Java language is essential.

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