24 lines
715 B
JavaScript
24 lines
715 B
JavaScript
const cds = require('@sap/cds')
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/** Service implementation for CatalogService */
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module.exports = cds.service.impl (function() {
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// Get entity definitions from reflected model
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const { Books } = cds.entities
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// Add some discount for overstocked books
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this.after ('READ', 'Books', each => {
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if (each.stock > 111) each.title += ` -- 11% discount!`
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})
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// Reduce stock of ordered books if available stock suffices
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this.on ('order', async (req) => {
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const {UPDATE} = cds.ql(req), {book,amount} = req.data
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const n = await UPDATE (Books, book)
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.where ('stock >=', amount)
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.set ('stock -=', amount)
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n > 0 || req.error (409,`${amount} exceeds stock for book #${book}`)
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})
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})
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