58 | Multiple joins did not return expected resultMultiple joins did not return expected result |
58 | Maven not OK for objectDBMaven not OK for objectDB |
11 | not possible to add an existing object to an array via explorernot possible to add an existing object to an array via explorer |
11 | JPA Entity Fields that do not participate in persistence and their values are never stored in the database (similar to transient fields in Java that do not participate in serialization). Static and final entity fields ... transient1; // not persistent because of static final int transient2 = 0; // not persistent |
11 | Retrieving JPA Entity Objects. The retrieval of objects does not require an active transaction because it does not change the content ... entity object is not found in the persistence context a new object is constructed and filled ... of the retrieved object to Employee is not required because find is defined as returning an instance |
10 | Collections in JPQL and Criteria Queries. as path expressions - in navigation to persistent collection fields. IS [NOT] EMPTY The IS [NOT] EMPTY operator checks whether a specified collection is empty or not. For example: c.languages IS EMPTY is TRUE if the collection is empty and FALSE otherwise. c.languages IS NOT EMPTY is FALSE |
9 | Logical Operators in JPQL and Criteria API || NOT ! JPQL follows the SQL notation, while Java uses its own notation (which is also in use by JDOQL ... || operator as a synonym for OR as part of its JDO support. Unary NOT (!) Operator The following query retrieves all the countries whose population does not exceed a specified limit: SELECT c FROM |
9 | Comparison in JPQL and Criteria API Equal To >= >= Equal = == Not Equal <> != The two sets differ in the Equal and the Not Equal operators ... . When both operands are not NULL (not shown in the table) the operator is evaluated to either TRUE or FALSE ... and expressions that include an unknown value are evaluated as unknown, i.e. to NULL. IS [NOT] NULL |
1 | [ODB1] Chapter 9 - ObjectDB Explorer Some JVM arguments can be useful. For instance, by default Java does not use more than 64MB ... . Otherwise, the required executable jar would not be found by explorer.exe. By default, running explorer.exe ... Explorer. In this way, the edited script will not be deleted when extracting files of a newer |
1 | [ODB1] Chapter 2 - A Quick Tour with the HelloWorld sample program, which is not JDO portable because it uses some ObjectDB extensions ... catch (JDOException x) { 23 // If not found - construct and store a new list ... (lines 12-13). If a database file does not exist in that path, a new database file is created |
