commands.md

Current working commands:

Note, all commands are ended by a ; All commands are case sensitive

---

INSERT

Inserts data into storage engine

To insert data, start a command with INSERT, like:

-- INSERT INTO *table* (*fields, fields...*)
INSERT INTO ... (..., ..., ...)
-- VALUES (*data to insert*)
VALUES (...);

• Currently this is a fixed table schema of (id, stop_name, rail_line)

Example

-- Sample insert
INSERT INTO Mbta (id, stop_name, rail_line)
VALUES (100, 'Englewood ave.', 'G');

• Commands don't need newlines to run, so the above example could also be run like:

-- Sample insert
INSERT INTO Mbta (id, stop_name, rail_line) VALUES (100, 'Englewood ave.', 'G');

SELECT

Queries data from the storage engine

To query data, start a command with SELECT, like:

-- SELECT FROM *table* (*fields, fields...*)
SELECT FROM ... (...);

Example

-- Sample query 
SELECT FROM Mbta (stop_name);  -- will return all stop names in db

Predicates

Currently a subset of predicates are supported:

• Equals: ==
• Not equal: <>
• greater than, less than, etc. : >, >=, <, <=

-- SELECT FROM *table* (*fields...*) WHERE predicate...
SELECT FROM ... (...)
WHERE ... == ...; 

Example

-- Sample query 
SELECT FROM Mbta (stop_name)
WHERE rail_line <> 'G';  -- Returns all stops not on the greenline (thank god)

---

Meta commands

• .help; -> Prints out help menu
• .tree; -> Prints out current tree layout and ids
• .exit; -> Exits SQCaml

---

That's all I have for now! 🐫︎