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It doesn't matter what DBMS you're using—Oracle, DB2, SQL Server, MySQL, PostgreSQL—misunderstandings can constantly come up over the correct meanings of phrases, misunderstandings that may have a major impact at the luck of your database tasks. for instance, listed below are a few universal database phrases: characteristic, BCNF, consistency, denormalization, predicate, repeating team, subscribe to dependency.
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Only the values TRUE and FALSE and the nonvalue NULL can be assigned to a BOOLEAN variable. The values TRUE and FALSE cannot be inserted into a database column. 1 31 LONG . Stores variable-length character strings. The LONG datatype is like the VARCHAR2 datatype, except that the maximum length of a LONG value is 2 gigabytes (GB). You cannot select a value longer than 4,000 bytes from a LONG column into a LONG variable. LONG columns can store text, arrays of characters, or even short documents.
B) What are the differences between named and anonymous PL/SQL blocks? ANSWER: Named PL/SQL blocks can be stored in the database and referenced later by their names. Because anonymous PL/SQL blocks do not have names, they cannot be stored in the database and referenced later. 1 9 BY THE WAY The SELECT statement in the preceding example is supported by multiple versions of Oracle. last_name; Notice that the FROM clause contains only one table, INSTRUCTOR. Following the FROM clause is the JOIN clause that lists the second table, SECTION.
To speak any foreign language, you have to begin by learning these character types. Then you learn how to make words from these character types. Finally, you learn the parts of speech, and you can begin talking. You can think of PL/SQL as being a more-complex language, because it has many character types and many types of words or lexical units that are made from these character types. As soon as you learn these, you can begin learning the structure of the PL/SQL language. CHARACTER TYPES The PL/SQL engine accepts four types of characters: letters, digits, symbols (*, +, –, =, and so on), and white space.