Relational Query Language (RQL) implements Relational Algebra operations on relational tables. It is a kind of a naive version of SQL supporting some standard commands given in section Features.

Compiling

Ensure that source code directory is writable. Run the following commands from src folder: g++ -std=c++11 -c relation.cpp database.cpp parse.cpp g++ parse.o relation.o database.o main.cpp -o rql

OR

Run compile.sh

Run

Run rql file from src folder.

Features

The following RQL statements can be used to create, query and modify database.

Standard Statements

1. create  tablename column_name1 datatype1, column_name2 datatype2,.....,  column_nameN datatypeN

2. insert tablename column_name1_value, column_name2_value,.....,  column_nameN_value

3. project tablename with column_name1 , column_name2 ,.....,  column_nameM 

4. select tablename with condition
	(where condition is fully bracketed.
	operands supported: ==,!=,>,<
	predicates can be joined using "and" or "or".
	)

5. rename old_tablename to new_tablename with column_name1 , column_name2 ,.....,  column_nameN 

6. tablename1 product tablename2

7. tablename1 join tablename2

8. tablename1 union tablename2

9. tablename1 intersect tablename2

10. tablename1 difference tablename2

11. input filename
(read commands from filename
sample: run "input query" to run sample query file in src folder 
)

12. show table tablename 

Nested query

Combine standard queries(except create,insert,input,show table) using braces(should be completely bracketed). Example: {{project {select student_grade with (id>2)} with id } intersect {project student_hostel with id} }

File Structure

• Folder db contains files for database tables.
• Folder headers contains header files made.
• Folder src contains c++ files for implementation of header files and main.cpp. It also contains sample query file.