Which collection is good for collecting information whose volume is unknown?

Asked By: Asuncion Pangerl | Last Updated: 9th April, 2020
Category: technology and computing databases
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Associative arrays are appropriate for relatively small lookup tables where the collection can be constructed in memory each time a procedure is called or a package is initialized. They are good for collecting information whose volume is unknown beforehand, because there is no fixed limit on their size.

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Similarly, you may ask, what are Oracle collections used for?

A collection can be loosely defined as a group of ordered elements, all of the same type, that allows programmatic access to its elements through an index. Commonly used collection types used in the programming world include arrays, maps, and lists. Storing elements in a collection can provide a number of advantages.

Also, what is the difference between record and collection in Oracle? In a collection, the internal components always have the same data type, and are called elements. To create a collection variable, you either define a collection type and then create a variable of that type or use %TYPE . In a record, the internal components can have different data types, and are called fields.

Thereof, what is PL SQL collections?

PL/SQL Collections. A collection is an ordered group of elements, all of the same type. It is a general concept that encompasses lists, arrays, and other data types used in classic programming algorithms. Each element is addressed by a unique subscript. These are similar to hash tables in other programming languages.

Which collection exception is raised when a subscript exceeds the number of elements in a collection?

Collection Exceptions

Collection Exception Raised in Situations
NO_DATA_FOUND A subscript designates an element that was deleted, or a nonexistent element of an associative array.
SUBSCRIPT_BEYOND_COUNT A subscript exceeds the number of elements in a collection.
SUBSCRIPT_OUTSIDE_LIMIT A subscript is outside the allowed range.

35 Related Question Answers Found

Is it good to use limit keyword with bulk collect?

No, we cannot use the LIMIT clause with SELECT-INTO statement. So always remember the LIMIT clause can only be used when you are using BULK COLLECT with FETCH-INTO statement. It cannot be used when you are using bulk collect with SELECT-INTO statement.

What is bulk collect in Oracle?

A bulk collect is a method of fetching data where the PL/SQL engine tells the SQL engine to collect many rows at once and place them in a collection. The SQL engine retrieves all the rows and loads them into the collection and switches back to the PL/SQL engine. All the rows are retrieved with only 2 context switches.

What is ref cursor in Oracle?

Introduction to REF CURSORs
Using REF CURSOR s is one of the most powerful, flexible, and scalable ways to return query results from an Oracle Database to a client application. A REF CURSOR is a PL/SQL data type whose value is the memory address of a query work area on the database.

What is dynamic query?

Dynamic queries refer to queries that are built dynamically by Drupal rather than provided as an explicit query string. All Insert, Update, Delete, and Merge queries must be dynamic. Select queries may be either static or dynamic. Therefore, "dynamic query" generally refers to a dynamic Select query.

Can we extend Varray in Oracle?

EXTEND is one of the Oracle PL/SQL collection methods which is used with nested tables and VARRAYS to append single or multiple elements to the collection. Note that EXTEND cannot be used with associative arrays.

What is the difference between nested table and Varray?

Difference b/w nested table and varray: Separate Table Space will be created for nested table which is other than the parent table's table space. If a varray size is less than 4 KB, it is stored inside the table of which it is a column otherwise, it is stored outside the table but in the same table space.

What is associative array in Oracle?

Introduction to Oracle PL/SQL associative arrays
Associative arrays are single-dimensional, unbounded, sparse collections of homogeneous elements. First, an associative array is single-dimensional. It means that an associative array has a single column of data in each row, which is similar to a one-dimension array.

What is PL SQL table in Oracle?

PL/SQL tables help you move bulk data. They can store columns or rows of Oracle data, and they can be passed as parameters. So, PL/SQL tables make it easy to move collections of data into and out of database tables or between client-side applications and stored subprograms.

Why do we use collections in PL SQL?

2) PL/SQL table or Associative array or Index b Mainly collection is used to improve the performance of the application. 3) By creating one collection variable in the PL/SQL script, We can reduce No. of variable declaration to store the value.

What is Pls_integer in PL SQL?

Definition: In Oracle PL/SL, PLS_INTEGER is a PL/SQL data type which belongs to the NUMBER family and used for storing signed integers. Since it uses machine arithmetic, it is usually faster in operations as compared to NUMBER data type. It value ranges from -2,147,483,647 to 2,147,483,647.

What is Varray in PL SQL?

The PL/SQL programming language provides a data structure called the VARRAY, which can store a fixed-size sequential collection of elements of the same type. A varray is used to store an ordered collection of data, however it is often better to think of an array as a collection of variables of the same type.

What is composite data type in PL SQL?

PL/SQL Composite data type - Collections (Associative array, VARRAY and Nested Tables ) A composite data type stores values that have internal components and internal components can be either scalar or composite. Internal components can be of same data type and different data type.

What is SQL Indexing?

An index is an on-disk structure associated with a table or view that speeds retrieval of rows from the table or view. These keys are stored in a structure (B-tree) that enables SQL Server to find the row or rows associated with the key values quickly and efficiently.

Is Record in Oracle PL SQL?

A PL/SQL record is a composite data structure that is a group of related data stored in fields. Each field in the PL/SQL record has its own name and data type.

Which type of collection is used while creating bulk collect?

You can use the BULK COLLECT clause with a SELECT INTO or FETCH statement to retrieve a set of rows into a collection (ie table of varray): of records.

Can we use commit inside trigger?

Yes, you can commit inside the trigger. But for this you have to make this trigger transaction to be an Independent transaction from its parent transaction, you can do this by using Pragma. Pragma AUTONOMOUS_TRANSACTION allow you to build the Independent (child) Transaction, started by another.

What is record type in PL SQL?

A Record type is a complex data type which allows the programmer to create a new data type with the desired column structure. It groups one or more column to form a new data type. These columns will have its own name and data type.