zs-core-db/src/services/oracle.js

Servicios generales de acceso a bases de datos

const oracle = require("oracledb");
oracle.fetchAsString = [oracle.CLOB];

process.platform === "win32" &&
  oracle.initOracleClient({
    libDir: process.platform && "c:\\oracle\\instantclient_21_13",
  });

const CONN = {
  __db: null,
};

let pool;

module.exports.connect = async (url) => {
  const user = url?.split("oracle://")[1].split(":")[0];
  const password = url?.split("oracle://")[1].split(":")[1].split("@")[0];
  const connectionString = url?.split("@")[1];

  pool =
    pool ??
    (await oracle.createPool({
      user,
      password,
      connectionString,
    }));

  const connection = await pool.getConnection();

  connection.query = this.query;
  const database = url.split("/").reverse()[0];
  CONN[database] = connection;
  this.use(database);

  return this;
};

module.exports.check = async (url) => {
  const db = CONN[url.split("/").reverse()[0]];
  await db.query({ sql: "select 'true' checked from dual" });
};

module.exports.use = (database) => {
  CONN.__db = CONN[database];
  return this;
};

module.exports.query = async ({
  sql = "",
  bind = {},
  sort = {},
  initial = 1,
  limit = 0,
  options,
}) => {
  const minRow = `"__min_row_${new Date().getTime()}"`;

  const pagedSQL =
    `select mn.* from (\n` +
    `select mx.*, rownum ${minRow} from (\n${sql}) mx \n` +
    `where rownum <= ${limit <= 0 ? "rownum" : initial + limit - 1}` +
    `) mn \nwhere mn.${minRow} >= ${initial}`;

  const result = (
    await CONN.__db.execute(pagedSQL, bind, {
      resultSet: true,
      outFormat: oracle.OUT_FORMAT_OBJECT,
    })
  ).resultSet;

  let row;
  const rows = [];
  while ((row = await result.getRow())) {
    delete row[minRow.slice(1, -1)];
    rows.push(row);
  }
  await result.close();

  return rows;
};

module.exports.execute = async (sql, bind) =>
  (await CONN.__db.execute(sql, bind)).rowsAffected;

module.exports.commit = async (sql, bind) => CONN.__db.commit();