node-oracledb/examples/selectjson.js

108 lines
3.6 KiB
JavaScript

/* Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved. */
/******************************************************************************
*
* You may not use the identified files except in compliance with the Apache
* License, Version 2.0 (the "License.")
*
* You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0.
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*
* See the License for the specific language governing permissions and
* limitations under the License.
*
* NAME
* selectjson.js
*
* DESCRIPTION
* Shows some JSON features of Oracle Database 12c.
* Requires Oracle Database 12.1.0.2, which has extensive JSON datatype support.
* See https://www.oracle.com/pls/topic/lookup?ctx=dblatest&id=ADJSN
*
* Uses Oracle's sample HR schema.
* Also run demo.sql to create the required extra table or do:
*
* DROP TABLE j_purchaseorder;
* CREATE TABLE j_purchaseorder
* (po_document VARCHAR2(4000) CONSTRAINT ensure_json CHECK (po_document IS JSON));
*
* This example uses Node 8's async/await syntax.
*
*****************************************************************************/
const oracledb = require('oracledb');
const dbConfig = require('./dbconfig.js');
async function run() {
let connection;
try {
connection = await oracledb.getConnection(dbConfig);
if (connection.oracleServerVersion < 1201000200) {
throw new Error('This example only works with Oracle Database 12.1.0.2 or greater');
}
let result;
console.log('Inserting Data');
const data = { "userId": 1, "userName": "Chris", "location": "Australia" };
const s = JSON.stringify(data);
await connection.execute(
`INSERT INTO j_purchaseorder (po_document) VALUES (:bv)`,
[s], // bind the JSON string for inserting into the JSON column.
{ autoCommit: true });
console.log('1. Selecting JSON stored in a VARCHAR2 column');
result = await connection.execute(
`SELECT po_document
FROM j_purchaseorder
WHERE JSON_EXISTS (po_document, '$.location')`);
const js = JSON.parse(result.rows[0][0]); // just show first record
console.log('Query results: ', js);
console.log('2. Using JSON_VALUE to extract a value from a JSON column');
result = await connection.execute(
`SELECT JSON_VALUE(po_document, '$.location')
FROM j_purchaseorder`);
console.log('Query results: ', result.rows[0][0]); // just show first record
if (connection.oracleServerVersion < 1202000000) {
throw new Error('These examples only work with Oracle Database 12.2 or greater');
}
console.log('3. Using dot-notation to extract a value from a JSON column');
result = await connection.execute(
`SELECT po.po_document.location
FROM j_purchaseorder po`);
console.log('Query results: ', result.rows[0][0]); // just show first record
console.log('4. Using JSON_OBJECT to extract relational data as JSON');
result = await connection.execute(
`SELECT JSON_OBJECT ('deptId' IS d.department_id, 'name' IS d.department_name) department
FROM departments d
WHERE department_id < :did`,
[50]);
for (let row of result.rows)
console.log(row[0]);
} catch (err) {
console.error(err);
} finally {
if (connection) {
try {
await connection.close();
} catch (err) {
console.error(err);
}
}
}
}
run();