Welcome to clinical data management program using SAS. In this video we will be discussing about the basic concepts of SAS programs that we will be using to do the practical session of clinical data management using SAS. So we will be discussing about SAS essentials the first topic that will be doing under SAS essential SAS SAS Data libraries. So first, let me explain you all what are the libraries libraries are like folders inside which the SAS data sets are located. in SAS, you have certain windows like results window explorer window editor window output window log window in the Explorer window or the SAS Data library, inside which the data sets are located. So here the concept of libraries are and data sets are explained with the help often real life example.

See, this is a word drop. In this word drop there are a number of drivers. These drivers are basically the libraries drove is my explorer window, and the files that we keep inside the drawers are my SAS data sets. Now let's discuss about the different types of SAS Data libraries. Basically there are two different types of SAS Data libraries. One is temporary library and another is permanent library.

Temporary library in SAS is called the work library, which is an inbuilt library they're in SAS but which by default is empty. If we create any SAS data sets inside the work library, then that those data sets are created and said work library. But once our SAS session is over, then the work library remains but the data sets inside the work library vanishes. Other than the work library. The rest of the libraries that are there in the Explorer window are all permanent libraries. See, for example, if we take the example of SAS user library is a permanent library.

It is an inbuilt permanent library of SAS, which consists of it Build SAS datasets. And here I have given another example of a library that is IR. Ir is a library that we are creating. Suppose we have got certain SAS data sets in our computer and we have to pull those data sets in SAS environment, then we have to create our own library to pull those data sets in the SAS environment. So for that, we have to create our own library and that library that we create that will be a permanent library. So the example of the permanent if you have given us a year you can give any name to the permanent library.

But you have to remember, though, we say that the library is permanent library, it is not permanent in nature. It is only existing during the time of our SAS session once a session gets over the library also vanishes. So every time you start the stat SAS session and you start accessing you want to access those data sets inside that particular libraries. You have to run a live name statement or you have to run a command To get that library back in your explorer window, or to get those data sets back in your SAS environment. Now let me explain your how to create your own library in SAS environment. That is how to get your SAS data sets in the SAS environment.

For this, you need to know you have to execute one live name statement. The live name statement starts with a keyword live name. Next is liberal liberal F stands for library meaning that you can give a name to your library and then we give within quotes we give the path of our data sets like where our SAS data sets are present in the our computer, that path we have to give there are certain rules which you have to maintain while naming are liberal that is, you have to maintain certain rules when naming your own library that is it should be eight characters or less. It should begin with a letter underscore remaining characters can be letters, numbers or underscores. So this T Live name statement is also considered as a global statement, because this statement is always executed individually. So you have to run this command or this statement before you start your SAS session in order to access those data sets to write this librium statement, then you have to give semicolon to access the SAS data sets.

So this is a way of how to create your own library. Next, let's come to the concept of temporary library as I told you that if suppose if you're creating any data set inside your temporary library see work in order to access those data sets in order to access any data set from the library in SAS. The general format of specifying the data set in our program is we have to write the library name dot the data set. But if our data set is present inside work, it is not necessary to specify the library name as work. Say for example, if we read work dot employees Like you want to access the data set employee located inside work we we have to write it in form of work dot employee. But if since employee data set is present in at work like library work dot employee is equivalent to writing only employee like if you write only employee just because it is located inside the work library, you will get the same output as writing only employ or if you write work don't imply you will get the similar but by chance if your data set is present in any other library, other than work then it is compulsory that you have to specify your library.

So, for work library, you need not specify the library name. It is optional, but for any other libraries other than work it is compulsory that you have to specify the library name to access the data set from that library. Next, these are the different concepts of SAS programs. The basic concept of SAS program is proc step and DATA step. And this is basic syntax for now you just have to remember that any program which starts with the keyword data is called a data step. Any program which starts with the keyword proc is proc step.

Okay? And every statement, every SAS tech statement ends by a semicolon you can write multiple statements in a single line provided that each statement is ending by a semicolon. But this is the most conventional way of writing that is writing multiple statements in multiple lines or we are writing a single statement in single line and if first statement is very long, then we can break it and write it in multiple lines. So this is a data step. This is our proc step, where we have done PROC PRINT data called work dot stuff, and then run. So let me tell you, there are two basic proc steps which you need to know that is PROC PRINT and proc contents.

PROC PRINT is used to display the data portion of the data set. That is the exact data set comes in our business. Including the observation number in your data set. We never have a serial number column by default. But when we do PROC PRINT on a particular data set, then in our report we will get our exact data set, including the serial number column or the observation column. And another is your proc contents data which is used to display the descriptive portion of the data set or we can say that it displays the data dictionary that is the name of the data set.

When was it created, how many variables are there in the data sets, how many observations are there whether they're character variables, whether the numeric variables are the data types of every variables are displayed. Another is proc means. proc means is used to display the descriptive statistics of our data. This is displayed only with respect to the numerical variables like if we have numerical variables in our data, then only the descriptive statistics of those variables are displayed. And here in this data set, we have imported our data. So these are certain examples.

We have Shown about DATA step and proc step. There are a number of other procedures and tasks that can be performed under under the DATA step or proc stuff. But I just wanted to give you an idea of the what is the concept of a data step and rock step, because these basic two concepts will be needed for us to do the practical session of clinical data management using SAS. So for now, we'll end this video over here. In our next video, we'll be doing the concept of accessing data. Thank you.

Good bye. See you all for the next video.