18 lines
604 B
JavaScript
18 lines
604 B
JavaScript
const cds = require('@sap/cds')
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module.exports = async (srv) => {
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const { Books } = srv.entities
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// Check all amounts against stock before activating
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srv.before(['CREATE', 'UPDATE'], 'Orders', (req) => {
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const tx = cds.transaction(req), order = req.data
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return Promise.all(order.Items.map(each => tx.run(
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UPDATE(Books).where({ ID: each.book_ID })
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.and(`stock >=`, each.amount)
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.set(`stock -=`, each.amount)
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).then(affectedRows => {
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if (!affectedRows) {
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req.error(409, `${each.amount} exceeds stock for book #${each.book_ID}`)
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}
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})))
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})
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} |