2. Database Language
• Structured Query Language (SQL) is the database
language by the use of which we can perform certain
operations on the existing database and also we can use
this language to create a database.
• SQL uses certain commands like Create, Drop, and Insert
etc. to carry out the required tasks.
Dr.Purnendu 2
3. • These SQL commands are mainly categorized into five categories as:
• DDL – Data Definition Language
• DML – Data Manipulation Language
• DQL-Data Query Language
• DCL – Data Control Language
• Though many resources claim there to be another category of SQL clauses TCL –
Transaction Control Language. So we will see in detail about TCL as well.
(https://www.geeksforgeeks.org/sql-ddl-dql-dml-dcl-tcl-commands/)
Dr.Purnendu 3
9. Click on (SQL WorkshopObject Browser) to see all the tables that we have created on
left hand side and on right side u can see the attributes and other info.
Dr.Purnendu 9
10. Import your CSV or excel data directly to work on that,
go to App Builderclick on create and then from a file
to upload ur csv/excel file
Dr.Purnendu 10
11. So now you can work around this table
Dr.Purnendu 11
13. Insert multiple rows(values) in the table, select all and then run.
Note:Remember that these commands may change for different platforms
(e.g MYSQL)
Dr.Purnendu 13
14. Apex command to insert multiple rows.
• begin
• INSERT INTO AI VALUES (76, 2023, 'clothings', 'Caps', 600, 0.99);
• INSERT INTO AI VALUES (77, 2022, 'Bikes', 'Touring Bikes', 6600, 0.90);
• end;
Dr.Purnendu 14
15. For MYSQL the multiple rows insertion follows this way.
So better choose 1 platform and work on it.
So in this course we will learn Apex Oracle and some
time MYSQL too.
Dr.Purnendu 15
17. Data Definition Language (DDL)
• Specification notation for defining the database schema
Example: create table instructor (
ID char(5),
name varchar(20),
dept_name varchar(20),
salary numeric(8,2))
• DDL compiler generates a set of table templates stored in a
data dictionary
• Data dictionary contains metadata (i.e., data about data)
• Database schema
• Integrity constraints
• Primary key (roll uniquely identifies student)
• Authorization
• Who can access what
Dr.Purnendu 17
18. Data Definition Language (DDL)
• Examples of DDL commands:
• CREATE – is used to create the database or its
objects (like table, index, function, views, store
procedure and triggers).
• DROP – is used to delete objects from the database.
• ALTER-is used to alter the structure of the database.
• TRUNCATE–is used to remove all records from a
table, including all spaces allocated for the records are
removed.
• COMMENT –is used to add comments to the data
dictionary.
• RENAME –is used to rename an object existing in the
database.
Dr.Purnendu 18
19. Alter in Apex Oracle: ALTER-is used to alter the structure of the database, Earlier the table Person_info
have attributes such as ( PersonID int, LastName varchar(255), FirstName varchar(255), Address
varchar(255), City varchar(255) ) but at line 2 and 3 we have added a new attribute named
phone_number.
Dr.Purnendu 19
22. Truncate will remove the data but table will still be there e.g here
data inside table Person_info will be deleted although table will still
be there.
Dr.Purnendu 22
23. After truncate we can see that data is not found, but we know that after
running truncate only data gets deleted but schema does not deletes. So to
check the schema type command (describe Person_Info)
Dr.Purnendu 23
25. So, now after running truncate all the data is removed only schema is left.
It is faster than DELETE as it removes all rows in a single operation.
Dr.Purnendu 25
26. Dropping Student table and then trying to see its
schema, it shows object not found that means
(Schema+Data) all dropped.
Dr.Purnendu 26
27. Delete: Here we have Created a table name AAA and inserted multiple values into it, now delete
the first row where AAA_ID=1, note here we will use ‘where’ clause and we will study about it in
coming sessions.
Dr.Purnendu 27
28. Delete Command: It may be slower than TRUNCATE
because it removes rows one at a time.
Before Delete
After running Delete
command
Dr.Purnendu 28
29. Activity 2: Do the following activities
1) Create a table (schema),
2) Add the rows(values) using insert,
3) Delete the table,
4) Truncate the table,
5) Apply all the Alter commands given at
(https://www.w3schools.com/sql/sql_alter.asp)
6) Drop that table.
Note: Have a screen shot of all these activities and mail me the
word format(extension: Name_Classrollno) at:
purnendu.pandey@kiet.edu
Dr.Purnendu 29
30. DML(Data Manipulation Language)
• DML(Data Manipulation Language) : The SQL commands that
deals with the manipulation of data present in the database belong to
DML or Data Manipulation Language and this includes most of the
SQL statements.
• Examples of DML:
• INSERT – is used to insert data into a table.
• UPDATE – is used to update existing data within a table.
• DELETE – is used to delete records from a database table.
• MERGE – is used to make changes in one table based on values
matched from anther. It can be used to combine insert, update,
and delete operations into one statement.
Dr.Purnendu 30
34. DCL(Data Control Language)
• DCL (Data Control Language): DCL includes commands
such as GRANT and REVOKE which mainly deals with the
rights, permissions and other controls of the database
system.
• Examples of DCL commands:
• GRANT-gives user’s access privileges to database.
• REVOKE-withdraw user’s access privileges given by
using the GRANT command.
Dr.Purnendu 34
