' Internal tables '

[Former Member]

hello friends..

v know their r 3 types of internal tables :

Standard

Sorted

Hashed..

can any one tell me in which scenario should i use which type of internal table.. with one ex ..

[Former Member]

Hi Shalu,

Standard Internal Tables:

Standard tables have a linear index. You can access them using either the index or the key. If you use the key, the response time is in linear relationship to the number of table entries. The key of a standard table is always non-unique, and you may not include any specification for the uniqueness in the table definition.

This table type is particularly appropriate if you want to address individual table entries using the index. This is the quickest way to access table entries. To fill a standard table, append lines using the (APPEND) statement. You should read, modify and delete lines by referring to the index (INDEX option with the relevant ABAP command). The response time for accessing a standard table is in linear relation to the number of table entries. If you need to use key access, standard tables are appropriate if you can fill and process the table in separate steps. For example, you can fill a standard table by appending records and then sort it. If you then use key access with the binary search option (BINARY), the response time is in logarithmic relation to the number of table entries.

Sorted Internal Tables:

Sorted tables are always saved correctly sorted by key. They also have a linear key, and, like standard tables, you can access them using either the table index or the key. When you use the key, the response time is in logarithmic relationship to the number of table entries, since the system uses a binary search. The key of a sorted table can be either unique, or non-unique, and you must specify either UNIQUE or NON-UNIQUE in the table definition. Standard tables and sorted tables both belong to the generic group index tables.

This table type is particularly suitable if you want the table to be sorted while you are still adding entries to it. You fill the table using the (INSERT) statement, according to the sort sequence defined in the table key. Table entries that do not fit are recognised before they are inserted. The response time for access using the key is in logarithmic relation to the number of table entries, since the system automatically uses a binary search. Sorted tables are appropriate for partially sequential processing in a LOOP, as long as the WHERE condition contains the beginning of the table key.

Hashed Internal Tables:

Hashes tables have no internal linear index. You can only access hashed tables by specifying the key. The response time is constant, regardless of the number of table entries, since the search uses a hash algorithm. The key of a hashed table must be unique, and you must specify UNIQUE in the table definition.

This table type is particularly suitable if you want mainly to use key access for table entries. You cannot access hashed tables using the index. When you use key access, the response time remains constant, regardless of the number of table entries. As with database tables, the key of a hashed table is always unique. Hashed tables are therefore a useful way of constructing and

using internal tables that are similar to database tables.

Standard:- For eg: if there are 10 rows..u want to search 7th row means..then standard type searches row by row. We generally use this type of internal table

Sorted :- It divides the 10 rows into half..then it matches the 7th row..If its in the next half it will againn divide and search untill the recdord is matched..

Hashed : It automatically searches the needed record.

Regards,

Satish

[Former Member]

Hi,

when u have large no of records in internal table and u want to process those records looping over the internal table, sorted or hashed tables offer better performance compared to std tables

[Former Member]

Dear Shalu,

Uses of Different types of Internal Tables:

=============================================

Standard Internal Table:

=============================================

> Used when the table has to be filled quickly. This is possible because the system does not have to check weather there are already existing entries.

=============================================

Sorted Internal Table:

=============================================

>As the name suggests this table is used where the data has to be in an order.

>Sorted tables are appropriate for partially sequential processing in a LOOP, as long as the WHERE condition contains the beginning of the table key.

=============================================

Hashed Internal Table:

=============================================

>Since Hashed tables are only accessed using its key the response time is independent of the number of table entries, and is constant. Therefore this table is used in scenarios fast retrieval of data is of utmost importance.

>Hashed tables are useful if you want to construct and use an internal table which resembles a database table or for processing large amounts of data.

=============================================

Best Regards,

Rajesh.

Please reward points if found helpful.

[Former Member]

Standard Internal Tables

Standard tables have a linear index. You can access them using either the index or the key. If you use the key, the response time is in linear relationship to the number of table entries. The key of a standard table is always non-unique, and you may not include any specification for the uniqueness in the table definition.

Use of Using Standard Internal Tables

This table type is particularly appropriate if you want to address individual table entries using the index. This is the quickest way to access table entries. To fill a standard table, append lines using the (APPEND) statement. You should read, modify and delete lines by referring to the index (INDEX option with the relevant ABAP command). The response time for accessing a standard table is in linear relation to the number of table entries. If you need to use key access, standard tables are appropriate if you can fill and process the table in separate steps. For example, you can fill a standard table by appending records and then sort it. If you then use key access with the binary search option (BINARY), the response time is in logarithmic relation to the number of table entries.

Sorted Internal Tables

Sorted tables are always saved correctly sorted by key. They also have a linear key, and, like standard tables, you can access them using either the table index or the key. When you use the key, the response time is in logarithmic relationship to the number of table entries, since the system uses a binary search. The key of a sorted table can be either unique, or non-unique, and you must specify either UNIQUE or NON-UNIQUE in the table definition. Standard tables and sorted tables both belong to the generic group index tables.

Use of using Sorted Internal Tables

This table type is particularly suitable if you want the table to be sorted while you are still adding entries to it. You fill the table using the (INSERT) statement, according to the sort sequence defined in the table key. Table entries that do not fit are recognised before they are inserted. The response time for access using the key is in logarithmic relation to the number of table entries, since the system automatically uses a binary search. Sorted tables are appropriate for partially sequential processing in a LOOP, as long as the WHERE condition contains the beginning of the table key.

Hashed Internal Tables

Hashes tables have no internal linear index. You can only access hashed tables by specifying the key. The response time is constant, regardless of the number of table entries, since the search uses a hash algorithm. The key of a hashed table must be unique, and you must specify UNIQUE in the table definition.

Use of using Hashed table

It is useful when your have to work with very big internal table .. Hashed table have the fastest access. Since you can access them only using the KEY access.

You need to use HASHED TABLE when you have lot of DATA table and want to read from that table based on UNIQUE key. You will get the best performance in this case.

Hashed tables cannot have duplicate entries. The key values are always unique and Hashed table have the fastest access. Since you can access them only using the KEY access.

The time access is constant !

Regards,

Maha

[Former Member]

Hi Shalu,

Standard tables

This is the most appropriate type if you are going to address the individual table entries using the index. Index access is the quickest possible access. You should fill a standard table by appending lines (ABAP APPEND statement), and read, modify and delete entries by specifying the index (INDEX option with the relevant ABAP command). The access time for a standard table increases in a linear relationship with the number of table entries. If you need key access, standard tables are particularly useful if you can fill and process the table in separate steps. For example, you could fill the table by appending entries, and then sort it. If you use the binary search option with key access, the response time is logarithmically proportional to the number of table entries.

Sorted tables

This is the most appropriate type if you need a table which is sorted as you fill it. You fill sorted tables using the INSERT statement. Entries are inserted according to the sort sequence defined through the table key. Any illegal entries are recognized as soon as you try to add them to the table. The response time for key access is logarithmically proportional to the number of table entries, since the system always uses a binary search. Sorted tables are particularly useful for partially sequential processing in a LOOP if you specify the beginning of the table key in the WHERE condition.

Hashed tables

This is the most appropriate type for any table where the main operation is key access. You cannot access a hashed table using its index. The response time for key access remains constant, regardless of the number of table entries. Like database tables, hashed tables always have a unique key. Hashed tables are useful if you want to construct and use an internal table which resembles a database table or for processing large amounts of data.