Difference between revisions of "LibreOffice-Suite-Base/C2/Tables-and-Relationships/English-timed"

||Welcome to the Spoken tutorial on LibreOffice Base.

||In this tutorial, we will cover Tables and Relationships in LibreOffice Base.  

||Here, we will learn about Adding data to a Table

||Define and create relationships

||In the previous LibreOffice Base tutorial, we introduced Base, database basics and learnt how to create a database and a table.  

||During the course of the tutorial we also created an example database called Library and created a Books table as well.  

||In this tutorial, we will resume with the Library database and learn how to add data to a table.

||For this, let us invoke the LibreOffice Base program.  

||For this, we will click on the Start button at the bottom left of the screen,  

||click on All programs, then click on LibreOffice Suite and LibreOffice Base.

||Since we already created the Library database in the last tutorial, this time we will just need to open it.

||To do so, let us click on the 'open an existing database file' option.

||In the 'Recently Used' drop down box, our Library database should be visible,

||So now, click on the Finish button.  

||If you don't see it, we can click on the Open button in the centre to browse to the Windows directory where Library database is saved.  

||Once found, click on the filename And click on the Open button.  

||Now, if LibreOffice Base program is already open, we can open the Library database from here,

||By clicking on the File menu on the top and then clicking on Open.  

||We will browse the Windows directory where the Library database file is saved.  

||Lets click on the file Library.odb and click on the Open button at the bottom.

||Now we are in the Library Database.  

||Let us click on the Tables icon in the Database list on the left panel.  

||Notice that the Books table appears in the Tables list on the right panel.

||Let us now right click on the Books table.  

||Let us now click on 'open', to add data to this table.

||Alternately, we can also double click on the table name to open it.

||A new window opens with the title 'Books – Library – LibreOffice Base: Table Data View'.  

||Now we can start entering data into the Books table, by typing in values directly into each cell.  

||Notice the Bookid column has 'AutoField',

||This means Base will assign ascending numbers automatically to each row of data that we insert.  

||Now, let us  input data into the cells, row by row, as shown on the screen.

||So, here we have 5 rows of sample data in our table Books.  

||Let us close the window, by clicking the File menu on the top and then choosing Close.

||Create a Members table that will store information about each member, for example, member name, and phone number.  

||Member Id with Field type Integer ,and make this the primary key

||Name with Fieldtype Text

||Phone with Fieldtype Text

||Okay, when you are done, this is how the Members table will look like.

||Now let us add 4 sample members into the Members table now as shown on the screen ,  

||just the way we did for the Books table.<pause for 10 seconds>

||Now, let us go back to the main window and click on the Tables Icon again.

||And let us create the third table: Books Issued.

||When done, the Books Issued table will have the following fields:

||Issue Id, Field type Integer. which will be the primary key

||Book Id,Field type,Integer

||Member Id ,Field type,Integer   

|Issue Date,Field type,Date   

||Return Date,Field type,Date   

||Actual Return Date,Field type,Date   

||And Checked In,Field type Yes/No Boolean

||Okay, we have created the Books Issued table,

||And now let us add the following sample data into it as you can see on the screen.

||Now, we have the three tables in our Library database, with sample data also.  

||Let us now learn about defining relationships in the database.

||So we created three tables to store three different sets of information.  

||Books, Members and Issue of Books to Members.  

||Now we also set up columns to uniquely identify each book, each member and each book issue in these three tables.  

||They are the Primary Keys.  

|One of the various advantages of a primary key is that it helps to establish relationships between tables.  

||Let us look at the Books Issued table. Here, we see the Book Id and Member Id fields.

|They can have any value in the Books Issued table.  

||But, they will need to correspond to the same values as we have in the Books and Members tables respectively.

||So if the book, Macbeth, has its Book Id as 3 in the Books table,

||Then by using 3 in the Book Id of the Books Issued table, we will still be referring to the same book.  

||So to explicitly connect these two tables, we will still need to link them someway.  

||Also, for example,How will you establish that 'Macbeth' was issued to Ravi Kumar on 2nd June 2011?  

||All of these can be achieved by setting up relationships, which helps interlink the data.  

|We will need to force Base to use values from the Books table and the Members table only, by linking the appropriate fields.  

||In the Libre Office Base main window, let us click on Tools and then click on Relationships.  

||This opens a small pop up window,

||Here we will select the top most table and click on the add button, and repeat for the other two tables also.  

||Close the pop up window.  

||Now we see the three tables Books, Books Issued and Members in a line.  

||Now, let us click on the Book Id in the Books table and drag and drop it on the Book Id in the Books Issued table.  

||Let us repeat the same for MemberId.  

||Click on the Member Id in the Members table and drag and drop it in the Books Issued table.  

||And therefore interlink meaningful data stored in various tables in the relational database.

||This brings us to the end of this tutorial on Tables and Relationships in LibreOffice

||To summarize, we learned how to: Add data to a table Define and create relationships

||Spoken Tutorial Project is a part of the Talk to a Teacher project, supported by the National Mission on Education through ICT, MHRD, Government of India.  

||This project is co-ordinated by http://spoken-tutorial.org.  

||This tutorial has been contributed by ...............................(Name of the translator and narrator)

 

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