26.oracleocp题库dba经典辅助学习

1、Managing Schema ObjectsObjectivesAfter completing this lesson, you should be able to do the following:Create and modify tablesDefine constraintsView the attributes of a tableView the contents of a tableCreate indexes and viewsWhat Is a Schema?HR schemaHR userownsSchemasSchemas created as part of the

2、 database creation process:SYSSYSTEMSample schemasSchemas - Full Notes PageAccessing Schema ObjectsClick a link to access the schema objects.Naming Database ObjectsNames must be from 1 to 30 bytes long with these exceptions:Names of databases are limited to 8 bytesNames of database links can be as l

3、ong as 128 bytesNonquoted names cannot be Oracle reserved words.Nonquoted names must begin with an alphabetic character from your database character set.Naming Database ObjectsNonquoted names can contain only Alphanumeric characters from your database character setThe underscore (_)Dollar sign ($)Po

4、und sign (#)No two objects can have the same name within the same namespaceSchema Object NamespacesThe following have their own namespace:IndexesConstraintsClustersDatabase triggersPrivate database linksDimensionsThe following are in the same namespace:TablesViewsSequencesPrivate synonymsStand-alone

5、 proceduresStand-alone stored functionsPackagesMaterialized viewsUser-defined typesSpecifying Data Types in TablesCommon data types:CHAR(size): Fixed-length character data of length size bytesVARCHAR2(size): Variable-length character string having maximum length size bytesDATE: Valid date range from

6、 January 1, 4712 BC to December 31, 9999 ADNUMBER(p,s): Number having precision p and scale sOther Data TypesFLOATINTEGERNCHARNVARCHAR2LONGLONG RAWRAWROWIDUROWIDBLOBCLOBNCLOBBFILETIMESTAMPOther Data TypesFull Notes PageCreating and Modifying TablesSpecify the table name and schema.Specify the column

7、 names, data types, and lengths.Creating and Modifying TablesFull Notes PageUnderstanding Data IntegrityUnderstanding Data IntegrityFull Notes PageDefining ConstraintsViewing the Attributes of a TableViewing the Contents of a TableActions with TablesActions with Tables Full Notes PageCreating Indexe

8、sWhat Is a View?Tailored representation of data in a table or viewViews do not contain dataCreating ViewsWhat Is a Sequence?What Is a Sequence? Full Notes PageUsing a SequenceSummaryIn this lesson, you should have learned how to:Create and modify tablesDefine constraintsView the attributes of a tableView the contents of a tableCreate indexes and viewsPractice 8: Working with TablesThis practice covers the following:Creating tables and indexesModifying tablesDropping a tableCreating a viewPr