150 | Internal ObjectDB error by read the primary keyInternal ObjectDB error by read the primary key |
113 | Inserted entities with strings as keys and indices needs more and more ram memory in comparing to primitive integers as keys and indicesHello, I have a problem with inserting of many entities. We use strings as primary key and indices ... ? See both examples. btc_es BTC EmbeddedSystems Correction. The case with strings as primary key and indices ... programs demonstrate well that automatic long primary keys are indeed much more efficient than String |
30 | Retrieving JPA Entity Objects of entity classes and to keep them as simple as possible. Retrieval by Class and Primary Key Every entity object can be uniquely identified and retrieved by the combination of its class and its primary key ... object whose primary key is 1: Employee employee = em.find(Employee.class, 1); Casting |
30 | Defining a JPA Entity Class, including which persistent types can be used for persistent fields, how to define and use a primary key ... you might have noticed that the Point entity class has no primary key (@Id) field. As an object database, ObjectDB supports implicit object IDs, so an explicitly defined primary key is not required. On the other hand |
29 | JPA Entity Fields (Mapped By) fields Primary key (ID) fields Version field The first three groups (transient, persistent ... two groups (primary key and version fields) can only be used in entity classes. Primary key fields are discussed in the Primary Key section. Transient Fields Transient entity fields are fields |
28 | Index Definition a unique field (similar to how primary keys behave). @Index represents either an ordinary index ... can only be defined on ordinary persistent fields (not on primary key / version fields). Composite Index ... is used as the BTree's primary sort key and which field is used as a secondary sort key. If x |
23 | Is ObjectDB better than competing object databases? databases do not support user defined primary keys, even though this is very useful in almost every application. ObjectDB supports user defined primary keys including composite primary keys. The support |
23 | Database Explorer and primary key separated by # (e.g. Point#1). A collection can be specified as a comma separated list ... to set a reference to an existing entity object, which has to be specified by type and primary key ... to an existing entity object, which has to be specified by type and primary key separated by # (e.g |
2 | javax.jdo.annotations.Keyjavax.jdo.annotations Annotation Key Target: Fields (including property get methods) Annotation for the key of a map relation. Corresponds to the xml element "key". Since: JDO 2.1 String column Name of the column to store the key in. Name of the column to store the key in. Returns: name |
2 | javax.jdo.JDOEntityManager) Find by primary key. Find by primary key. Search for an entity of the specified class and primary key ... there. Parameters: entityClass - entity class primaryKey - primary key Returns: the found entity instance or null ... an entity type or the second argument is is not a valid type for that entity’s primary key or |
