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Varrays versus Nested TablesThe Nested tables are differing from varrays in the following ways:1) Varrays have a maximum size, while nested tables do not.2) Varrays are always dense, while nested tables can be sparse. Therefore, you can delete individual elements from a nested table but not from a varray.3) The Oracle stores varray data in-line (in similar tablespace). But, the Oracle stores nested table data out-of-line in a store table, that is a system-generated database table related with the nested table.4) When stored in the database, the varrays retain their ordering and subscripts, while nested tables do not.Which collection type must you use? That totally depends on your wants and the size of the collection. The varray is stored as an opaque object, while a nested table is stored in a storage table with each element mapped to a row in the table. Therefore, if you want efficient queries, then use the nested tables. If you want to retrieve the whole collections as a whole, then use varrays. Though, when collections get very large, it becomes impractical to retrieve more than subsets. Therefore, varrays are better suited for the small collections
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Creating a Table Syantax: CREATE TABLE ENROLMENT (StudentId SID, Name VARCHAR (30) NOT NULL, CourseId CID, PRIMARY KEY (StudentId, CourseId)) ; Explan
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Cursor Attributes The Cursors and cursor variables have 4 attributes which give you helpful information about the execution of a data manipulation statement. Syntax:
heap sort program in pl/sql
V ariables and Constants in PL/SQL The PL/SQL permits you to declare constants and variables, and then use them in SQL and procedural statements anywhere in the expression. Th
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