89 lines
2.9 KiB
JavaScript
89 lines
2.9 KiB
JavaScript
'use strict';
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const db = require('../infra/db');
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const AUTO_COLUMNS = new Set(['id', 'created_at', 'updated_at']);
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const columnsCache = new Map();
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/**
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* 取表列名（缓存）。DDL 稳定，进程级缓存即可。
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* @param {string} table
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* @returns {Promise<string[]>}
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*/
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async function getColumns(table) {
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if (columnsCache.has(table)) return columnsCache.get(table);
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const rows = await db.query(
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`SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS
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WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = ?
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ORDER BY ORDINAL_POSITION`,
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[table],
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);
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const cols = rows.map((r) => r.COLUMN_NAME);
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columnsCache.set(table, cols);
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return cols;
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}
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/**
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* 依据表实际列，推断按月过滤条件（兼容三种月份维度命名）。
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* 无月份维度（字典/全量表）→ 返回空条件。
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* @param {string[]} columns
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* @param {number} year
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* @param {number} month
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* @returns {{ clause: string, params: any[] }}
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*/
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function monthWhere(columns, year, month) {
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if (columns.includes('exam_year') && columns.includes('exam_month')) {
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return { clause: 'exam_year = ? AND exam_month = ?', params: [year, month] };
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}
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if (columns.includes('year') && columns.includes('month')) {
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return { clause: '`year` = ? AND `month` = ?', params: [year, month] };
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}
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if (columns.includes('missing_month')) {
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return { clause: 'missing_month = ?', params: [`${year}-${String(month).padStart(2, '0')}`] };
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}
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return { clause: '', params: [] };
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}
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/**
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* 值归一化：对象/数组转 JSON 字符串；Buffer/Date/标量原样；undefined→null。
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* @param {any} v
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*/
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function coerceValue(v) {
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if (v === undefined || v === null) return null;
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if (Buffer.isBuffer(v) || v instanceof Date) return v;
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if (typeof v === 'object') return JSON.stringify(v);
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return v;
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}
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/**
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* 生成多行 INSERT（列 = 表列 ∩ 行键，排除自增/时间戳自动列）。
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* @param {string} table
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* @param {string[]} tableColumns
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* @param {Object[]} rows
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* @returns {{ sql: string, params: any[], columns: string[] } | null} 无有效列时返回 null
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*/
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function buildMultiInsert(table, tableColumns, rows) {
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const rowKeys = new Set();
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for (const r of rows) for (const k of Object.keys(r)) rowKeys.add(k);
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const columns = tableColumns.filter((c) => !AUTO_COLUMNS.has(c) && rowKeys.has(c));
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if (columns.length === 0) return null;
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const placeholderRow = `(${columns.map(() => '?').join(', ')})`;
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const sql =
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`INSERT INTO \`${table}\` (${columns.map((c) => `\`${c}\``).join(', ')}) ` +
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`VALUES ${rows.map(() => placeholderRow).join(', ')}`;
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const params = [];
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for (const r of rows) for (const c of columns) params.push(coerceValue(r[c]));
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return { sql, params, columns };
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}
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/** 将数组按 size 切块 */
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function chunk(arr, size) {
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const out = [];
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for (let i = 0; i < arr.length; i += size) out.push(arr.slice(i, i + size));
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return out;
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}
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module.exports = { getColumns, monthWhere, coerceValue, buildMultiInsert, chunk };
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