摘要：Number FunctionsROUND:Rounds value to a specified deciamlTRUNC:Truncates value to a specified decimalMOD:Returns remainder fo divisionFunctionResultROUND(45.926,2)45.93TRUNC(45.926,2)45.92MOD(1600,300)100Demo-01:Using the ROUND FunctionSQL> SELECT ROUND(45.923,2),ROUND(45.923,0),ROUND(45.923,-1) 阅读全文

摘要：ObjectivesAfter completing this lesson,you should be able to do the following:Describe various types of functions available in SQL.Use character,number,and date functions in SELECT statements.Lesson AgendaSingle-row SQL functionsCharacter functionsNumber functionsWorking with datesDate functions/* 函 阅读全文

摘要：SynonymCreating a Synonym for an Object Simplify access to objects by creating a synonym(another name for an object).With synonyms ,you can：Create an easier reference to a table that is owned by another user Shorten length object namesCREATE [PUBLIC] SYNONYM synonym FRO object; PUBLIC关键词，如果指定了，则全局都可 阅读全文

摘要：Indexes是可选项，可有可无；它存在的价值就是improves the performance of some queries.An index:Is a schema object Can be used by the Oracle server to speed up the retrieval of rows by using a pointerCan reduce disk input/output(I/O) by using a rapid path access method to locate data quicklyIs independent of the table t 阅读全文

摘要：ObjectivesAfter completing this lesson,you should be able to do the following:Categorize the main database objectsReview the table structureList the data types that are available for columns.Create a simple tableExplain how constraints are created at the time of table creation.Describe how schema ob 阅读全文

摘要：SequencesA sequence:Can automatically generate unique numbersIs a shareable objectCan be used to create a primary key valueReplace application codeSpeeds up the efficiency of accessing sequence values when cached in memory.CREATE SEQUENCE Statement SyntaxDefine a sequence to generate sequential numb 阅读全文

摘要：ObjectivesAfter completing this lesson,you should be able to do the following:Create simple and complex views.Retrieve data from views.Create,maintain,and use sequences.Create and maintain indexes.Create private and public synonyms.Lesson AgendaOverview of views-Creating,modifying,and retrieving dat 阅读全文