DDIC Objects

[Former Member]

Hi ,

I need simple definitions on each Data dictionary objects ?

[Former Member]

Hi,

check this link for detailed explanation:

http://www.allsaplinks.com/data_dictionary_all.html

check this for more info:

http://www.sapbrain.com/FAQs/TECHNICAL/SAP_ABAP_DATADICTIONARY_FAQ.html

keerthi

[Former Member]

try this SAP Help -

http://help.sap.com/saphelp_nw2004s/helpdata/en/cf/21ea0b446011d189700000e8322d00/frameset.htm

[Former Member]

Hi Kumar,

http://help.sap.com/printdocu/core/Print46c/en/data/pdf/BCDWBDIC/BCDWBDIC.pdf

In the data type you can maintain the following elements..

DATA ELEMENTS

STRUCTURES

TABLE TYPES..

o Data elements (elementary types)

Elementary types have no structure. They describe the data type

attributes (such as given Dictionary data type, number of places)

and information that is relevant for the screen (such as title) of

unstructured data objects (variables/fields).

o Structures (structured types)

Structured types describe the structure and functions of any

structured data objects, that is of data structures with components

of any type.

A component can be a field with an elementary type or can itself be

a structure. A table can also be used as a component in a structure.

A database table always has a structure and is therefore implicitly

a structured type. However, the fields of a database table can only

have an elementary type.

o Table types

Table types describe the structure and functions of internal tables

in the ABAP program. Their rows can have any row type. Table types

with elementary row type therefore can be defined just the same as

multi-dimensional table types (table types with a table type as row

type) or table types using structures with table-like components.

Press F1 in the data type field..You will get a detailed documentation.

Regards,

Priyanka.

[Former Member]

Hi,

These are the objects in Data Dictionary

<b>Data types</b>

Data types are the actual type definitions in the ABAP Dictionary. They allow you to define elementary types, reference types, and complex types that are visible globally in the system. The data types of database tables are a subset of all possible types, namely flat structures.

<b>Data Elements</b>

Data elements in the ABAP Dictionary describe individual fields. They are the smallest indivisible units of the complex types described below, and are used to specify the types of columns in the database. Data elements can be elementary types or reference types.

<b>Structures</b>

A structure is a sequence of any other data types from the ABAP Dictionary, that is, data elements, structures, table types, or database tables. When you create a structure in the ABAP Dictionary, each component must have a name and a data type. In an ABAP program, you can use the TYPE addition to refer directly to a structure.

If you define a local data type in a program by referring to a structure as follows:

TYPES <t> TYPE <structure>.

<b>Table Types</b>

Table types are construction blueprints for internal tables that are stored in the ABAP Dictionary.

When you create a table type in the ABAP Dictionary, you specify the line type, access type, and key. The line type can be any data type from the ABAP Dictionary, that is, a data element, a structure, a table type, or the type of a database table. You can also enter a predefined Dictionary type directly as the line type, in the same way that you can with a domain.

<b>Type Groups</b>

Before Release 4.5A, it was not possible to define standalone types in the ABAP Dictionary to which you could refer using a TYPE addition in an ABAP program. It was only possible to refer SAP AG BC - ABAP Programming

Data Types in the ABAP Dictionary to flat structures. Structures in programs corresponded to the structures of database tables or structures in the ABAP Dictionary. In ABAP programs, you could only refer to database tables and structures in the ABAP Dictionary using LIKE. It was, however, possible to refer to individual components of the Dictionary type. Complex local data types such as internal tables or deep structures had no equivalent in the ABAP Dictionary. The solution to this from Release 3.0 onwards was to use type groups. Type groups were based on the include technique, and allowed you to store any type definitions globally in the Dictionary by defining them using TYPES statements.

Rgda,

Prakash

[Former Member]

Hi ,

Thanks .

If i could get on Views , Lock Objects , Search Helps . It would be nice ?

[Former Member]

Views:

There are 4 types views are avilable in SAP.

Database View - To club more than one table

Projection View - To hide fields in one table

Maintanance View - To maintain database records in table

Help View - To provide help for a fields (Same functionality as Search help. This is outdated)

View are improves perfromance in the following aspects

1. If you want to use more than two table in 'JOIN' condition better to use Views . It will improves performance of a program

2. If you want to use mutiple FOR ALL ENTRIES clause, better to club all SELECT statement in a view.

Lock Objects:

Lock objects are use in SAP to avoid the inconsistancy at the time of data is being insert/change into database.

SAP Provide three type of Lock objects.

- Read Lock(Shared Locked)

protects read access to an object. The read lock allows other transactions read access but not write access to

the locked area of the table

- Write Lock(exclusive lock)

protects write access to an object. The write lock allows other transactions neither read nor write access to

the locked area of the table.

- Enhanced write lock (exclusive lock without cumulating)

works like a write lock except that the enhanced write lock also protects from further accesses from the

same transaction.

You can create a lock on a object of SAP thorugh transaction SE11 and enter any meaningful name start with EZ Example EZTEST_LOCK.

Use: you can see in almost all transaction when you are open an object in Change mode SAP could not allow to any other user to open the same object in change mode.

Example: in HR when we are enter a personal number in master data maintainance screen SAP can't allow to any other user to use same personal number for changes.

Technicaly:

When you create a lock object System automatically creat two function module.

1. ENQUEUE_<Lockobject name>. to insert the object in a queue.

2. DEQUEUE_<Lockobject name>. To remove the object is being queued through above FM.

You have to use these function module in your program.

Search Helps:

See the below link to understand this completely:

http://help.sap.com/saphelp_nw2004s/helpdata/en/cf/21ee93446011d189700000e8322d00/frameset.htm

Thanks

[Former Member]

Hi,

check this for search helps:

http://help.sap.com/saphelp_nw04/helpdata/en/cf/21ee2b446011d189700000e8322d00/content.htm

views:

http://help.sap.com/saphelp_webas620/helpdata/en/cf/21ec5d446011d189700000e8322d00/content.htm

lock objects:

Lock objects are use in SAP to avoid the inconsistancy at the time of data is being insert/change into database.

SAP Provide three type of Lock objects.

- Read Lock(Shared Locked)

protects read access to an object. The read lock allows other transactions read access but not write access to

the locked area of the table

- Write Lock(exclusive lock)

protects write access to an object. The write lock allows other transactions neither read nor write access to

the locked area of the table.

- Enhanced write lock (exclusive lock without cumulating)

works like a write lock except that the enhanced write lock also protects from further accesses from the

same transaction.

reward if helpful,

keerthi

[Former Member]

Hi,

<b>SAP Locks</b>

To complement the SAP LUW concept, in which bundled

database changes are made in a single database LUW, the

R/3 System also contains a lock mechanism, fully

independent of database locks, that allows you to set a

lock that spans several dialog steps. These locks are

known as SAP locks.

The SAP lock concept is based on lock objects. <b>Lock

objects</b> allow you to set an SAP lock for an entire

application object. An application object consists of

one or more entries in a database table, or entries from

more than one database table that are linked using

foreign key relationships.

Before you can set an SAP lock in an ABAP program, you

must first create a lock object in the ABAP Dictionary.

A lock object definition contains the database tables

and their key fields on the basis of which you want to

set a lock. When you create a lock object, the system

automatically generates two function modules with the

names ENQUEUE_<lock object name> and DEQUEUE_<lock

object name>. You can then set and release SAP locks in

your ABAP program by calling these function modules in a

CALL FUNCTION statement.

<b>ABAP Dictionary Views</b>

You can define joins between database tables statically

and systemwide as views in the ABAP Dictionary. ABAP

Dictionary views can be used by all ABAP programs. One

of their advantages is that fields that are common to

both tables (join fields) are only transferred once from

the database to the application server.

Views in the ABAP Dictionary are implemented as inner

joins. If the inner table contains no lines that

correspond to lines in the outer table, no data is

transferred. This is not always the desired result. For

example, when you read data from a text table, you want

to include lines in the selection even if the

corresponding text does not exist in the required

language. If you want to include all of the data from

the outer table, you can program a left outer join in

ABAP.

The links between the tables in the view are created and

optimized by the database system. Like database tables,

you can buffer views on the application server. The same

buffering rules apply to views as to tables. In other

words, it is most appropriate for views that you use

mostly to read data. This reduces the network load and

the amount of physical I/O in the database.

<b>3 types of views</b>

<b>Projection view</b>

Just retrieves some fields from only one table.

<b>Help view</b>

This is used for search help.

<b>Database view</b>

This is inner join view.

<b>Search Helps</b>

A search help is a ABAP Dictionary object used to define possible values (F4) help .

You can link a search help to a parameter as follows:

PARAMETERS <p> ... MATCHCODE OBJECT <search_help>.

The search help <search_help> must be defined in the ABAP Dictionary. The system now automatically displays the input help button for the field on the screen and activates the F4 key for it. When the user requests input help, the hit list of the search help appears, and when he or she selects an entry, the corresponding export parameter is placed in the input field.

The predecessors of search helps in the ABAP Dictionary were called matchcode objects, hence the name of the addition in the PARAMETERS statement. Existing matchcode objects are still supported.

Rgds,

Prakash

[Former Member]

<b>What is an ABAP data dictionary?-</b>

ABAP 4 data dictionary describes the logical structures of the objects used in application development and shows how they are mapped to the underlying relational database in tables/views

[Former Member]

Hi Kumar,

Lock objects:

http://www.sap-img.com/abap/type-and-uses-of-lock-objects-in-sap.htm

http://help.sap.com/saphelp_nw04s/helpdata/en/cf/21eea5446011d189700000e8322d00/content.htm

Match Code Objects:

http://help.sap.com/saphelp_nw2004s/helpdata/en/41/f6b237fec48c67e10000009b38f8cf/content.htm

http://searchsap.techtarget.com/tip/0,289483,sid21_gci553386,00.html

Views

There are 4 types views are avilable in SAP.

Database View - To club more than one table

Projection View - To hide fields in one table

Maintanance View - To maintain database records in table

Help View - To provide help for a fields (Same functionality as Search help. This is outdated)

View are improves perfromance in the following aspects

1. If you want to use more than two table in 'JOIN' condition better to use Views . It will improves performance of a program

2. If you want to use mutiple FOR ALL ENTRIES clause, better to club all SELECT statement in a view.

check this

https://forums.sdn.sap.com/click.jspa?searchID=234671&messageID=2590691

Search helps.

These are two types.

Elementary n Collective.

1) Elementary search helps describe a search path. The elementary search help must define where the data of the hit list should be read from (selection method), how the exchange of values between the screen template and selection method is implemented (interface of the search help) and how the online input help should be defined (online behavior of the search help).

2) Collective search helps combine several elementary search helps. A collective search help thus can offer several alternative search paths.

3)An elementary search help defines the standard flow of an input help.

4) A collective search help combines several elementary search helps. The user can thus choose one of several alternative search paths with a collective search help.

5)A collective search help comprises several elementary search helps. It combines all the search paths that are meaningful for a field.

6)Both elementary search helps and other search helps can be included in a collective search help. If other collective search helps are contained in a collective search help, they are expanded to the level of the elementary search helps when the input help is called.

http://help.sap.com/saphelp_nw04/helpdata/en/cf/21ee38446011d189700000e8322d00/content.htm

http://help.sap.com/saphelp_nw04/helpdata/en/cf/21ee45446011d189700000e8322d00/content.htm

Regards,

Priyanka.