Tpes of Internal Table in ABAP

Tpes of Internal Table in ABAP

Internal tables are used to access a data in a fixed structure and storing it in working memory in ABAP. The data is stored line by line in memory, and each line(record) has the same structure.
Standard Internal Tables

Standard Internal Tables are default internal tables.

We can use either key or index operation to read an entry .

we can use either linear search or binary search to search for an entry, .

We can Apply sort operation.

If you are going to address the individual table entries using the index. Index access is the quickest possible access ,this is the best suitable table.

We can use insert and append to add records.

It have an internal linear index.

The system can access records either by using the table index or the key.

The response time for key access is proportional to the number of entries in the table.

The key of a standard table is always non-unique.

You cannot specify a unique key.

This means that standard tables can always be filled very quickly, since the system does not have to check whether there are already existing entries.
Sorted Internal Tables

These are a special type of internal tables, where data is automatically sorted as you insert the record.

Sorted tables are always saved sorted by the key.

They also have an internal index.
The system can access records either by using the table index or the key.

The response time for key access is logarithmically proportional 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.

When you define the table, you must specify whether the key is to be UNIQUE or NON-UNIQUE. Standard tables and sorted tables are known generically as index tables.

We use either key or index operation to read a record .

This is the most suitable type if you want a table which is sorted as you fill it. You process sorted tables using the INSERT statement.

You use binary search as data is already sorted for searching an entry.

You can't sort as data is already sorted.

You can apply insert, not append.

Hashed Internal Tables

Hashed tables have no linear index.

You can only access a hashed table using its key.

The response time is independent of the number of table entries, and is constant, since the system access the table entries using a hash algorithm.

The key of a hashed table must be unique. When you define the table, you must specify the key as UNIQUE.

These are used with logical databases i:e with all fields and all records.

Index operation is not possible, you only use key operation.

You use hashed algorithm to search for any entry.

Which are mostly used in ABAP with BI projects

This is the most suitable when you use 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.
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