Friday, December 30
Web Dynpro ABAP Applications
When some one cannot carry a computer and he wants something that is a bit handy , takes his PDA with him and wants to make a place order . He just has to log in on his PDA and open the website GOI which has been created altogether from ABAP . So everything becomes so easy for the client . It is like any other web page where you can just point and click you web browser and open the web page and open your application. Once we create a Web dynpro application , a URL has been created . For example, in ABAP , once we create a module pooled program , we have to create a transaction code for it .
We open the module pooled program using the transaction code which we write on the top left , like SE 80 is a transaction code for the ABAP code . Then SE 38 is the transaction code for the program . So we can create a transaction code like be SAP order . Similarly , web dynpro will also have a transaction code but we don’t call it a transaction but we call it an application . The application would be a URL . So the transaction code for the web dynpro will be a URL . So we have to launch web dynpro based URL which would be global . So if we are connected to your SAP system , it only ask us the team log in ID page in which we have to enter our SAP log in ID and password . The same ID and same password which you use . After log in you can input feeds . If there is a button to create , then you can create a place order or a purchase order or some purchase requisition or anything that is needed .
So web dynpro applications can only be run on a browser . Meaning that the browser could be either on an ipad or a computer or a mobile and its not like that we can run these web dynpro applications only on the stand alone SAP systems . And along with that there is one more thing to be added that not all the mobile phones can run web dynpro applications because it needs a proper browser . Most of the cheaper phones would contain browser which needs light based web page . It means that very lighter web page , it converts into the phone format and then displays the things . This is a drawback that it does not support each and every mobile handset , like the phone should be a windows , or a blackberry or iphone. So you can see that its basically those phones in which JAVA applications can run as of now . But there can be modifications in the future . The main benefits with the web dynpro application is as we said , we have minimized coding efforts and maximize the designs . All these have been done with the help of web dynpro meta data. In the meta data , external files for UI and external codes for UI and the HTML codes and all will be taken care of with the meta data . Meta data is like the tool designed by us to create a web dynpro application as a screen in which you can see that in that panel there will be some of the UI buttons .
We have to click on the UI buttons and drag it on the screen . For example , if we want to see an input feed , click on the input field UI and drag on the screen . This way an input feed would be created . On looking at the buttons itself you can learn which is the input button or which is the output button . We don’t have to code for the UI . We don’t have to really write the codes to create an input or output feed . So all the codes that the UI as seen is generated by the meta data . The meta data can be used for the tools to create certain ABAP applications . So web dynpro tool is used in meta data to create feed and just we have to engage our code in few places where web dynpro meta data would be able to place the right business logic . For example if there is a table displayed and if we want to get something from the table from the database , the we have to definitely access the web database . We have to write the codes to read the data from the database or if we want to make some dynamical changes , then all the things that we have to take care , the meta data would be taking care of the UI for the navigations on the screen and each time the screen is changed , which may or may not control the good changed screen .
So in practice , the meta data would take care of all the changes in navigations , the UI changes , the changes in the screen . There is a separate layout or logic . The layout would be the second advantage of web dynpro . If there is a separate layout , we would create the layout of the screen separately and logic would be written separately . We don’t have to mix up things in between . Everything would be there in place and if we would want to change something then we can go there and we can change . So nothing else is complex in this . Everything is on the place it has to be . It also supports web services and data banding . One more thing with web dynpro is a declarative programming approach with the minimal coding which we can get . As a part of this training lets also see examples of web services with data banding . Without data banding nothing can be shown on the screen . With data banding its something like this , if we want to display a table , and we need to display a value which is coming from the database , behind the view is the context for each and every view in which we have to define the data which is being bound to each and every UI . Lets assume that we want to show the values of the table which we want to show on the UI . So there is a table on the UI to which we have to bind the values with .
We have to keep the data in this context . It is very well coded and it also supports the web services where we can create sales order or purchase order . For each and every transaction there is a back up . So if we want to create a similar transaction which is there in SAP, we can use the web services . Hence we can take the advantage of such services . The main advantage which we have with web dynpro is the SAP web application , so all the applications which are on the web services can be consumed by web dynpro . Lets see about the meta data declaration and the custom coding .This means that the meta data model which is where we don’t have to define a code and the custom code is where we have to write a code . The meta data will take care of the UI part of the generator or the navigation . There would be a generated code for the UI , or in the navigation if there is anything changing on the screen on click of a button , all these things would be taken care of at the meta data and there would a place on the generator code itself where our codes would be embedded . Everything would be combined and would be given as an application . To run this application we would require an URL .
The URL for the web dynpro component is called an application . So in order to run each and every thing we would require an application . The thing we could do for the fellow world would be to open the internet explorer page see how this works , like where is the place for meta data , where is the place for the custom code and how we are able to launch these web dynpro in ABAP applications . We have some advantages of team meta model also . There is a screen layout and in the screen layout also you can create the screens in the navigation and error handling , like if we want to move from one view to another view , there is a log in screen and then there is a welcome screen . We have created a log in screen and then we have created a welcome screen and now we have to link a navigation .
Each of these things would be taken care of by the meta model . If there is an error by the log in like if we click on login and if the user is not authentically created , then that error handling would also be taken care by the meta model and we do not have to code . And along with that if we click on log in and if we want to take on data from the first screen . For example on log in we give our user name , we give our password , and we give the session like we want a particular session , it then moves to the second welcome page and here the session would be the thing that would be helping to move to the second screen . So the data flows from the first screen to the second one by the meta model . We don’t have to code anything . These are the advantages of meta model and the custom coding will be done as we move into ABAP .
We have to click on the UI buttons and drag it on the screen . For example , if we want to see an input feed , click on the input field UI and drag on the screen . This way an input feed would be created . On looking at the buttons itself you can learn which is the input button or which is the output button . We don’t have to code for the UI . We don’t have to really write the codes to create an input or output feed . So all the codes that the UI as seen is generated by the meta data . The meta data can be used for the tools to create certain ABAP applications . So web dynpro tool is used in meta data to create feed and just we have to engage our code in few places where web dynpro meta data would be able to place the right business logic . For example if there is a table displayed and if we want to get something from the table from the database , the we have to definitely access the web database . We have to write the codes to read the data from the database or if we want to make some dynamical changes , then all the things that we have to take care , the meta data would be taking care of the UI for the navigations on the screen and each time the screen is changed , which may or may not control the good changed screen .
So in practice , the meta data would take care of all the changes in navigations , the UI changes , the changes in the screen . There is a separate layout or logic . The layout would be the second advantage of web dynpro . If there is a separate layout , we would create the layout of the screen separately and logic would be written separately . We don’t have to mix up things in between . Everything would be there in place and if we would want to change something then we can go there and we can change . So nothing else is complex in this . Everything is on the place it has to be . It also supports web services and data banding . One more thing with web dynpro is a declarative programming approach with the minimal coding which we can get . As a part of this training lets also see examples of web services with data banding . Without data banding nothing can be shown on the screen . With data banding its something like this , if we want to display a table , and we need to display a value which is coming from the database , behind the view is the context for each and every view in which we have to define the data which is being bound to each and every UI . Lets assume that we want to show the values of the table which we want to show on the UI . So there is a table on the UI to which we have to bind the values with .
We have to keep the data in this context . It is very well coded and it also supports the web services where we can create sales order or purchase order . For each and every transaction there is a back up . So if we want to create a similar transaction which is there in SAP, we can use the web services . Hence we can take the advantage of such services . The main advantage which we have with web dynpro is the SAP web application , so all the applications which are on the web services can be consumed by web dynpro . Lets see about the meta data declaration and the custom coding .This means that the meta data model which is where we don’t have to define a code and the custom code is where we have to write a code . The meta data will take care of the UI part of the generator or the navigation . There would be a generated code for the UI , or in the navigation if there is anything changing on the screen on click of a button , all these things would be taken care of at the meta data and there would a place on the generator code itself where our codes would be embedded . Everything would be combined and would be given as an application . To run this application we would require an URL .
The URL for the web dynpro component is called an application . So in order to run each and every thing we would require an application . The thing we could do for the fellow world would be to open the internet explorer page see how this works , like where is the place for meta data , where is the place for the custom code and how we are able to launch these web dynpro in ABAP applications . We have some advantages of team meta model also . There is a screen layout and in the screen layout also you can create the screens in the navigation and error handling , like if we want to move from one view to another view , there is a log in screen and then there is a welcome screen . We have created a log in screen and then we have created a welcome screen and now we have to link a navigation .
Each of these things would be taken care of by the meta model . If there is an error by the log in like if we click on login and if the user is not authentically created , then that error handling would also be taken care by the meta model and we do not have to code . And along with that if we click on log in and if we want to take on data from the first screen . For example on log in we give our user name , we give our password , and we give the session like we want a particular session , it then moves to the second welcome page and here the session would be the thing that would be helping to move to the second screen . So the data flows from the first screen to the second one by the meta model . We don’t have to code anything . These are the advantages of meta model and the custom coding will be done as we move into ABAP .
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