Goal
I had to insert sample data in a database:
- Users
- username
- enabled
- Products
- name
- description
- price
Random Int
Generate a random integer between 1 and 1000 and return it as a string:
let rand_price () = string_of_int (1+ (Random.int 999)) ;;
Random Char
Generate a random lowercase character (between 'a' and 'z'). 'a' ASCII code is 97 and the 26 following letters are the 26 following numbers:
let rand_chr () = (Char.chr (97 + (Random.int 26)));;
Random vowel
Generate a random character until it matches a vowel. Please add a comment if you would suggest another algorithm:
let rec rand_voy () =
let got = (rand_chr ())
in
match got with
| 'a' | 'e' | 'i' | 'o' | 'u' | 'y' -> got
| _ -> rand_voy ();;
Random consonant
Generate a random character until it doesnt matche a vowel. Please add a comment if you would suggest another algorithm:
let rec rand_con () =
let got = (rand_chr ())
in
match got with
| 'a' | 'e' | 'i' | 'o' | 'u' | 'y' -> rand_con ()
| _ -> got ;;
Random syllable(s)
In this document, a syllable is a consonant followed by a vowel. Generate a finite number of random syllables:
let rec rand_convoy acc syll_number () =
match syll_number with
| 0 -> acc;
| _ -> rand_convoy (acc ^ (Char.escaped (rand_con ())) ^ (Char.escaped(rand_voy()))) (syll_number - 1) ();;
The final goal is to use all this as a "string", so we make "char" to "string"
conversion at this level with the "Char.escaped" function.
Random short word
Short word: between 3 and 6 syllables.
(* mot: entre 3 et 6 syllabes *)
let rand_word () = (rand_convoy "" (3 + (Random.int 3)) ());;
Wel will also need a fixed length word, of 4 syllables.
(* nom: 4 syllabes c'est tout *)
let rand_name () = rand_convoy "" 3 ();;
Random sentence
Random sentence is a random number of random words. We will limit the number of words (to avoid bloating the database). Wel will end the sentences with a ".".
let rec rand_sentence acc word_number () =
match word_number with
| 0 -> (acc ^ (rand_word ()) ^ ".");
| _ -> rand_sentence (acc ^ (rand_word ()) ^ " ") (word_number - 1) ();;
Utilities
Generate a "description", and quote a string in preparation for INSERT in the database:
let rand_description () = rand_sentence "" (10 + (Random.int 10)) ();;
let sql_quote a_string = "'"^a_string^"'";;
let generate_insert_user () = "INSERT INTO users VALUES ("^sql_quote (rand_name ())^" ,1)" ;;
let generate_insert_product p_id =
"INSERT INTO products VALUES ("^(string_of_int p_id)^", '"^(rand_name ())^"', '"^(rand_description ())^"', "^(rand_price ())^")";;
SQLite filling
SQLite manipulation has already been introduced in another post.
let db = Sqlite3.db_open "/var/www/database.db";;
Sqlite3.exec db (generate_insert_user ());;
let rec fill_users number =
match number with
| 0 -> ()
| _ ->
Sqlite3.exec db (generate_insert_user ()) ;
fill_users (number-1);
();;
let rec fill_products number =
match number with
| 0 -> ()
| _ ->
Sqlite3.exec db (generate_insert_product number) ;
fill_products (number-1);
();;
