What are the different types of collections in Oracle?

What are the different types of collections in Oracle?

PL/SQL has three collection types—associative array, VARRAY (variable-size array), and nested table.

What is the use of collections in Oracle?

To use collections in an application, you define one or more PL/SQL types, then define variables of those types. You can define collection types in a procedure, function, or package. You can pass collection variables as parameters to stored subprograms.

What is dense and sparse in Oracle collection?

Dense: If all the rows between the first and last are defined and given a value (including NULL) Sparse: Not defined or populated sequentially. There are gaps between defined rows. VARRAYS are always dense as we cannot delete values in between and the values can only be deleted from the end (using TRIM).

Is PL SQL record a collection type?

PL/SQL Records A record is a collection of data objects that are kept in fields, each having its own name and datatype. You can declare a PL/SQL record that resembles a row in a database table without listing all the columns using the % ROWTYPE attribute.

What is table type in Oracle?

The most common type of table in an Oracle database is a relational table, which is structured with simple columns similar to the employees table. Two other table types are supported: object tables and XMLType tables. Any of the three table types can be defined as permanent or temporary.

What is collections in Oracle and list few collections?

Collections and records are composite types that have internal components that can be manipulated individually, such as the elements of an array, record, or table. A collection is an ordered group of elements, all of the same type.

What are ref CURSORs in Oracle?

A REF CURSOR is a PL/SQL data type whose value is the memory address of a query work area on the database. In essence, a REF CURSOR is a pointer or a handle to a result set on the database. REF CURSOR s are represented through the OracleRefCursor ODP.NET class.

Which collection is sparse by nature?

At the time of creating the collection, the subscript type should be mentioned. These collections are not stored sequentially. They are always sparse in nature. The array size is not fixed.

What is Oracle Pragma?

Also called apseudoinstruction, a pragma simply passes information to the compiler rather than getting transformed into a particular execution. The syntax for using the PRAGMA keyword is as follows: PRAGMA instruction ; where instruction is a statement providing instructions to the compiler.

What are collectioncollections in Oracle PL/SQL?

Collections in Oracle PL/SQL. Oracle uses collections in PL/SQL the same way other languages use arrays. Oracle provides three basic collections, each with an assortment of methods. This article was originally written against Oracle 8i, but it includes operators, conditions and functions that were added in later releases.

What is the difference between a type and a collection?

First we are creating type, then only we are creating a variable of that type. A collection is an ordered group of elements, all of the same type. Each element is identified by a unique subscript that represents its position in the collection The main purpose of using collection is to improve application performance.

What is collection in Java?

A collection is an ordered group of elements, all of the same type. Each element is identified by a unique subscript that represents its position in the collection The main purpose of using collection is to improve application performance. By using collections]

What is the difference between index-by tables and nested table collections?

SQL> In Oracle 9i Release 2 these have been renamed to Associative Arrays and can be indexed by BINARY INTEGER or VARCHAR2. Nested table collections are an extension of the index-by tables. The main difference between the two is that nested tables can be stored in a database column but index-by tables cannot.