Mihamina Rakotomandimby

Goal

I had to insert sample data in a database:

• Users
  • username
  • enabled
• Products
  • name
  • description
  • price

All should be random, and to "benchmark" the rendering (HTML/CSS), I must make the effort to have different text and number length. I decide to generate the sample data with OCaml.

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); 
              ();;