Previously we have discussed Node.js Database connectivity with PostgreSQL.Today I have a prepared a complete tutorial of Basic SQL Operations like Creation,Insertion and Selection.We have discussed these Operations in different three cases.
Case 1: for creating a table
Case 2: for Inserting values
Case 3: for Selection Operation
const readline = require('readline');
const rl = readline.createInterface({
input: process.stdin,
output: process.stdout
});
console.log("Press 1 for create new table");
console.log("Press 2 for insert Operation");
console.log("Press 3 for fetch Data from Database");
rl.question('Enter your choice? ', (choice) => {
var inputChoice = parseInt(choice);
var pg = require("pg");
var connectStr = "pg://postgres:root_123@localhost:5432/NewDatabase";
var client = new pg.Client(connectStr);
client.connect();
switch (inputChoice) {
case 1:
// Create table
var executeQuery = client.query("CREATE TABLE IF NOT EXISTS empDetail(firstname varchar(64), lastname varchar(64))");
executeQuery.on("end", () => {
client.end();
});
console.log("Your table has been created ...");
break;
case 2:
// Insert details inside table
var executeQuery = client.query("Insert Into empDetail(firstname, lastname) values('Ronald', 'McDonal')");
executeQuery.on("row", function(row, result) {
result.addRow(row);
});
console.log("Your Insert Operation has been Completed");
break;
case 3:
// Select details from table
console.log("You wnat to retreive Data");
var executeQuery = client.query("SELECT * From empDetail");
executeQuery.on("end", function(result) {
var empDetail = JSON.parse(JSON.stringify(result.rows, null, " "));
console.log(empDetail.length);
for (var i = 0; i < empDetail.length; i++) {
console.log("Details ::" + empDetail[i].firstname + " ********* " + empDetail[i].lastname);
}
});
break;
default:
console.log("Wrong Choice ");
break;
}
rl.close();
});
OutPut :
