Build database

I would solve this problem as follows using R . I will set the number of rows in my database:

n <- 200

I'm going to create n random values for the precipitation, temperature and presence of snakes with the exponential, normal and binomial distributions, respectively:

set.seed(1234) # para que os resultados sejam reproduziveis
precipitacao <- round(rexp(n, rate=2), digits=1)
temperatura  <- round(rnorm(n, mean=25), digits=0)
presenca     <- rbinom(n, size=1, prob=0.2)

Then I'm going to create a vector called estacao , with the defined seasons:

estacao <- rep(c(1, 2, 3, 4), each=n/4)

Finally, all together in a single object, called data:

dados <- data.frame(precipitacao, temperatura, presenca, estacao)
head(dados)
##    precipitacao temperatura presenca estacao
## 1           1.3          25        0       1
## 2           0.1          23        0       1
## 3           0.0          26        0       1
## 4           0.9          26        0       1
## 5           0.2          27        0       1
## 6           0.0          26        0       1
## 7           0.4          26        1       1
## 8           0.1          25        0       1
## 9           0.4          25        1       1
## 10          0.4          27        0       1

Note that I did not assume any kind of dependency between the variables. For example, the generation of numbers indicating the presence or absence of snakes will not have, in this example, a relation to recorded precipitation or temperature. Everything here was generated in a random and independent way. Perhaps the data collected in the future does not exhibit this behavior.

In PostgreSQL you can use the random() function to simulate such data without the need for an external language, with SQL only. I imagine it's something easily transportable to other database systems.

First, I created a table with the specifications given in the question:

create table presenca_de_cobras (
  precipitacao numeric(4,1) not null,
  temperatura int not null,
  presenca boolean not null,
  estacao int not null,
  constraint estacoes check (estacao in (1,2,3,4))
);

Each field must have a different data range, such as precipitation in hundreds of millimeters, I imagine, and the presence of snakes in boolean "true" or "false."

The random() function returns a random value of 0 to 1, so multiply by the maximum limit of the value in question. In addition to random() , I used the floor() function to round down the station random value and generate_series() to build a hundred-register table, but I do not need the data it returns. All of this is passed to INSERT that will populate the table:

-- insere os dados
insert into presenca_de_cobras 
select 
  (random()*200)::numeric(4,1) precipitacao,  -- precipitacao de 0-200 milimetros
  (random()*40)::int temperatura,             -- temperatura de 0-40 graus
  (random() > 0.5) presenca,                  -- presenca TRUE ou FALSE
  floor(random()*4+1)::int estacao            -- estação de 1-4
from generate_series(1,100) as s;

Finally, just check the table itself:

select * from presenca_de_cobras limit 10;

| precipitacao | temperatura | presenca | estacao |
|--------------|-------------|----------|---------|
|        137.2 |          16 |    false |       4 |
|        164.5 |          38 |    false |       3 |
|          4.3 |          14 |     true |       3 |
|        134.9 |          38 |    false |       2 |
|          3.9 |          18 |    false |       3 |
|         67.3 |          37 |    false |       1 |
|        140.3 |          34 |     true |       3 |
|         34.2 |          35 |     true |       4 |
|         56.3 |          37 |     true |       1 |
|        171.5 |           5 |     true |       4 |

Follow SQL Fiddle with all the steps: link

I believe the database can be created with the following commands:

CREATE DATABASE Estudo;
CREATE TABLE Persons (
id int,
precipitacao varchar(255),
temperatura varchar(255),
estacao varchar(255),
presenca Serpente boolean 
);

That's how popular the table is as you want, I hope I have helped.

You can start with the

CREATE TABLE table_name (
    column1 datatype,
    column2 datatype,
    column3 datatype,
   ....
);