Differences
EJB QL is a database query language similar to SQL. The used queries are somewhat different from relational SQL, as it uses a so-called "abstract schema" of the enterprise beans instead of the relational model. In other words, EJB QL queries do not use tables and their components, but enterprise beans, their persistent state, and their relationships. The result of an SQL query is a set of rows with a fixed number of columns. The result of an EJB QL query is either a single object, a collection of entity objects of a given type, or a collection of values retrieved from CMP fields. One has to understand the data model of enterprise beans in order to write effective queries.
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Famous quotes containing the word differences:
“I may be able to spot arrowheads on the desert but a refrigerator is a jungle in which I am easily lost. My wife, however, will unerringly point out that the cheese or the leftover roast is hiding right in front of my eyes. Hundreds of such experiences convince me that men and women often inhabit quite different visual worlds. These are differences which cannot be attributed to variations in visual acuity. Man and women simply have learned to use their eyes in very different ways.”
—Edward T. Hall (b. 1914)
“Quintilian [educational writer in Rome about A.D. 100] hoped that teachers would be sensitive to individual differences of temperament and ability. . . . Beating, he thought, was usually unnecessary. A teacher who had made the effort to understand his pupil’s individual needs and character could probably dispense with it: “I will content myself with saying that children are helpless and easily victimized, and that therefore no one should be given unlimited power over them.””
—C. John Sommerville (20th century)
“Toddlerhood resembles adolescence because of the rapidity of physical growth and because of the impulse to break loose of parental boundaries. At both ages, the struggle for independence exists hand in hand with the often hidden wish to be contained and protected while striving to move forward in the world. How parents and toddlers negotiate their differences sets the stage for their ability to remain partners during childhood and through the rebellions of the teenage years.”
—Alicia F. Lieberman (20th century)