Witold swierzy patch 3

data-platform/autonomous-database/autonomous-json/oracle-api-for-mongodb-demos/NodeJS/README.md

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+## NodeJS demos
+This directory contains NodeJS scripts using Oracle API for MongoDB and demonstrating its capabilities
+
+## License
+
+Copyright (c) 2025 Oracle and/or its affiliates.
+
+Licensed under the Universal Permissive License (UPL), Version 1.0.
+
+See [LICENSE](https://github.com/oracle-devrel/technology-engineering/blob/main/LICENSE) for more details.

data-platform/autonomous-database/autonomous-json/oracle-api-for-mongodb-demos/NodeJS/hr/00_utils.js

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+const {MongoClient} = require('mongodb');
+const fs = require('fs');
+
+async function displayExecutionPlan(db,collection,statement,hint) {
+    if (hint !== undefined)
+        result = await db.collection(collection).find(statement).hint(hint).explain();
+    else
+        result = await db.collection(collection).find(statement).explain();
+    console.log(result.queryPlanner);
+}
+
+async function displaySQLExecutionPlan(db,sqlStatement) {
+    result = db.aggregate([ {$sql: {statement: sqlStatement}}]).explain();
+    console.log((await result).stages[0].$sql);    
+}
+
+async function getDBVersion(db) {
+    let oracle_api = !(await isNativeMongoDB(db));
+
+    if (oracle_api) {
+        result = db.aggregate([{ $sql: "select version_full from product_component_version" }] );
+        return (await result.toArray())[0].VERSION_FULL;
+    }
+    else
+        return (await db.admin().serverInfo()).version;
+}
+
+async function isNativeMongoDB(db) {    
+    return !(await db.admin().serverInfo()).hasOwnProperty("oramlVersion");    
+}
+
+async function prepareSchema(db) {
+    let data_set_dir  = process.env.DATA_SET_DIR;
+    let oracle_api = !(await isNativeMongoDB(db));
+
+    // EMPLOYEES relational table cleaning up
+    if (oracle_api) {
+        result = db.aggregate([{ $sql: "truncate table employees"}]);
+        for await (res of result);
+        result = db.aggregate([{ $sql: "truncate table departments"}]);
+        for await (res of result);
+    }
+
+    // DEPARTMENTS_COL and EMPLOYEES_COL preparation
+    let departmentsArrayFile = data_set_dir + "/departments.json";
+    let employeesArrayFile   = data_set_dir + "/employees.json";
+    let departments = JSON.parse(fs.readFileSync(departmentsArrayFile));
+    let employees   = JSON.parse(fs.readFileSync(employeesArrayFile));
+
+    // dropping views
+    await db.dropCollection("DEPARTMENTS_COL_VW");       //  view based on collection
+    if (oracle_api) {
+        await db.dropCollection("DEPARTMENTS_TAB_VW");    // JSON Collection view based on table
+        await db.dropCollection("DEPARTMENTS_DUAL_VW");   // JSON Duality View based on table
+        await db.dropCollection("EMPLOYEES_DUAL_VW");     // JSON Duality View based on table
+        await db.dropCollection("DEPT_EMP_COL");
+    }
+
+    // dropping collections
+    await db.dropCollection("DEPARTMENTS_COL");
+    await db.dropCollection("EMPLOYEES_COL");
+    await db.dropCollection("DEPARTMENTS_COL_BKP");
+
+    // load data into DEPARTMENTS_COL collection
+    await db.createCollection("DEPARTMENTS_COL");
+    await db.collection("DEPARTMENTS_COL").insertMany(departments);
+    // load data into EMPLOYEES_COL collection
+    await db.createCollection("EMPLOYEES_COL");
+    await db.collection("EMPLOYEES_COL").insertMany(employees);
+}
+
+function sleep(ms) {
+    return new Promise((resolve) => setTimeout(resolve, ms));
+}
+
+module.exports = {displayExecutionPlan,displaySQLExecutionPlan,isNativeMongoDB,prepareSchema,getDBVersion,sleep};

data-platform/autonomous-database/autonomous-json/oracle-api-for-mongodb-demos/NodeJS/hr/01_clear_db.js

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+const utils         = require("./00_utils");
+const {MongoClient} = require("mongodb");
+
+async function clear_db() {   
+    let client        = new MongoClient(process.env.MONGO_URI);
+    let db            = client.db();
+    let oracle_api    = !(await utils.isNativeMongoDB(db));
+
+    let colls=[];
+    let collName = "";
+    let numColls = 0;
+
+    try {
+        console.log("Cleaning up the database schema.");
+        await utils.prepareSchema(db);
+        console.log("Database schema is clear.");
+    }
+    catch (e) {
+        console.error(e);
+    }  
+    finally {
+        await client.close();
+        console.log("Disconnected from database.");
+    }
+}
+
+clear_db().catch(console.error);

data-platform/autonomous-database/autonomous-json/oracle-api-for-mongodb-demos/NodeJS/hr/02_basic_demo.js

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+const utils         = require("./00_utils");
+const {MongoClient} = require("mongodb");
+
+async function basic_demo() {   
+    let client        = new MongoClient(process.env.MONGO_URI);
+    let db            = client.db();
+    let oracle_api    = !(await utils.isNativeMongoDB(db));
+
+    let colls=[];
+    let collName = "";
+    let numColls = 0;
+
+    try {
+        console.log("Preparing the database schema.");
+        await utils.prepareSchema(db);
+        console.log("Database schema prepared.");
+
+        if (oracle_api)
+            console.log("You are connected to an Oracle MongoDB API service.");
+        else
+            console.log("You are connected to a native MongoDB database.");
+
+        // 1. list databases
+        databasesList = await db.admin().listDatabases();
+        console.log("Databases:");
+        databasesList.databases.forEach(db => console.log(` ${db.name}`));    
+
+        // 2. list collections in the default database
+        colls = (await db.listCollections().toArray());
+        console.log("Number of collections : "+colls.length);
+        console.log("Collections : ");
+        for ( i = 0; i < colls.length; i++ )
+            console.log(" "+colls[i].name);    
+
+        // 3. insert documents into DEPARTMENTS_COL collection
+        console.log("Inserting department 120 - HR into DEPARTMENTS_COL collection");
+        db.collection("DEPARTMENTS_COL").insertOne(
+            {"_id" : 120, "department_name" : "Human Resources"}
+        );
+        console.log("Department 120, Human Resoures inserted.");
+
+        console.log("Inserting departments 130, 140 and 150 using insertMany method");
+        db.collection("DEPARTMENTS_COL").insertMany([
+            {"_id" : 130, "department_name" : "Department 130"},
+            {"_id" : 140, "department_name" : "Department 140"},
+            {"_id" : 150, "department_name" : "Department 150"}
+        ]);
+        console.log("Departments 130, 140 and 150 inserted.");
+
+        // 4. reading data from DEPARTMENTS_COL collection
+        console.log("Reading all documents from DEPARTMENTS_COL collection");
+        depts = db.collection("DEPARTMENTS_COL").find().sort( {"_id" : 1} );
+        for await (dept of depts)
+            console.log("id : " + dept._id + " name : " + dept.department_name);
+
+        // 5. joining data from two collections
+        console.log("Query joining DEPARTMENTS_COL and EMPLOYEES_COL collections");
+        depts = db.collection("DEPARTMENTS_COL").aggregate
+        ([{ 
+            $lookup : { from         : "EMPLOYEES_COL",
+                        localField   : "_id",
+                        foreignField : "department_id",
+                        as           : "EMPLOYEEES" }
+        }]);
+        for await (dept of depts) {
+            console.log(dept);
+        }
+
+        // 6. create a backup collection and copying the data
+        console.log("Creating DEPARTMENTS_COL_BKP collection.");
+        await db.createCollection("DEPARTMENTS_COL_BKP");
+        console.log("Collection DEPARTMENTS_COL_BKP created.");
+
+        console.log("Copying data from DEPARTMENTS_COL to DEPARTMENTS_COL_BKP.");
+        depts = db.collection("DEPARTMENTS_COL").find().sort( {"_id" : 1} );
+        for await (dept of depts) {
+            await db.collection("DEPARTMENTS_COL_BKP").insertOne(dept);
+            console.log("Department #"+dept._id+" copied to backup collection.")
+        }
+        console.log("Backup completed.");
+        console.log("Number of copied documents : " + (await db.collection("DEPARTMENTS_COL_BKP").countDocuments()));
+    }   
+    catch (e) {
+        console.error(e);
+    }  
+    finally {
+        await client.close();
+        console.log("Disconnected from database.");
+    }
+}
+
+basic_demo().catch(console.error);

data-platform/autonomous-database/autonomous-json/oracle-api-for-mongodb-demos/NodeJS/hr/03_expr.js

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+const utils         = require("./00_utils");
+const {MongoClient} = require("mongodb");
+
+async function expr() { 
+    let client        = new MongoClient(process.env.MONGO_URI);
+    let db            = client.db();
+    let oracle_api    = !(await utils.isNativeMongoDB(db));
+
+    try {
+        console.log("Preparing the database schema.");
+        await utils.prepareSchema(db);
+        console.log("Database schema prepared.");
+
+        if (oracle_api)
+            console.log("You are connected to an Oracle MongoDB API service.");
+        else
+            console.log("You are connected to a native MongoDB database.");
+
+        if (!oracle_api) {
+           console.log("You are using native MongoDB service. $expr operator is fully supported.");
+           emps = db.collection("EMPLOYEES_COL").find({$expr: {$lt: ["$manager_id","$_id"]}});
+        }
+        else {
+           try {
+                console.log("Query using $expr operator.");
+                console.log("db.EMPLOYEES_COL.find({$expr: {$lt: ['$manager_id','$_id']}})")
+                emps = db.collection("EMPLOYEES_COL").find({$expr: {$lt: ["$manager_id","$_id"]}});
+                for await (emp of emps) {
+                    console.log(emp.last_name + " " + emp.first_name);         
+                }  
+           }
+           catch (e) {
+                console.log("You are using Oracle MongoDB API. $epr operator has limited support.");
+                console.error(e);
+           }
+           console.log("You are using Oracle MongoDB API. There is need to use $sql operator instead of $expr.");
+           console.log("Query : select c.DATA from EMPLOYEES_COL c where c.DATA.manager_id < c.DATA.'_id'");
+           emps = db.aggregate([{ $sql: 'select c.DATA from EMPLOYEES_COL c where c.DATA.manager_id < c.DATA."_id"' }] ); 
+           console.log("Execution plan : ");
+           await utils.displaySQLExecutionPlan(db,'select c.DATA from EMPLOYEES_COL c where c.DATA.manager_id < c.DATA."_id"');
+        }
+        for await (emp of emps)
+            console.log(emp.last_name + " " + emp.first_name); 
+    }   
+    catch (e) {
+        console.error(e);
+    }  
+    finally {
+        await client.close();
+        console.log("Disconnected from database.");
+    }
+}
+
+expr().catch(console.error);

data-platform/autonomous-database/autonomous-json/oracle-api-for-mongodb-demos/NodeJS/hr/04_mongo_views.js

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+const utils         = require("./00_utils");
+const {MongoClient} = require("mongodb");
+const fs = require('fs');
+
+async function views() {
+    let client        = new MongoClient(process.env.MONGO_URI);
+    let db            = client.db();
+    let oracle_api    = !(await utils.isNativeMongoDB(db));
+    let data_set_dir  = process.env.DATA_SET_DIR;
+    let departmentsArrayFile = data_set_dir + "/departments.json";
+    let employeesArrayFile   = data_set_dir + "/employees.json";
+
+    try {
+        console.log("Preparing the database schema.");
+        await utils.prepareSchema(db);
+        console.log("Database schema prepared.");
+
+        console.log("Creating view DEPARTMENTS_COL_VW based on DEPARTMENTS_COL collection");
+        await db.createCollection("DEPARTMENTS_COL_VW",{viewOn : "DEPARTMENTS_COL", pipeline : [] } ); 
+        console.log("DEPARTMENTS_COL_VW read-only view created.");
+
+
+        console.log("Checking the execution plan of a query using the view");
+        console.log("Query : db.DEPARTMENTS_COL_VW.find({{ '_id' : {$lte : 80 }}})");
+        depts = db.collection("DEPARTMENTS_COL_VW").find({ "_id" : {$lte : 80 }});
+        for await (dept of depts) 
+            console.log(dept._id+" "+dept.department_name);
+        await utils.displayExecutionPlan(db,"DEPARTMENTS_COL_VW",{ "_id" : {$lte : 80 }});
+        try {
+            console.log("Trying to update DEPARTMENTS_COL_VW");
+            result = await db.collection("DEPARTMENTS_COL_VW").updateOne({_id:190},{$set:{department_name:"NoName"}});
+            console.log("Number of modified rows : "+result.modifiedCount);
+            if (oracle_api) {
+                console.log("You are using Oracle MongoDB API.");
+                console.log("Updates on collection views don't raise any exceptions, but are just ignored.");
+            }
+        }
+        catch (e) {
+            if (!oracle_api)
+                console.log("You are connected to a native MongoDB instance. Updates on VIEWS raise exceptions.");
+            console.error(e);    
+        }
+    }   
+    catch (e) {
+        console.error(e);
+    }  
+    finally {
+        await client.close();
+        console.log("Disconnected from database.");
+    }
+}
+
+views().catch(console.error);