105 lines
2.4 KiB
JavaScript
105 lines
2.4 KiB
JavaScript
var _ = require('underscore');
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var BaseWidget = require('./base');
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var debug = require('debug')('windshaft:widget:formula');
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var dot = require('dot');
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dot.templateSettings.strip = false;
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var formulaQueryTpl = dot.template([
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'SELECT',
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'{{=it._operation}}({{=it._column}}) AS result,',
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'(SELECT count(1) FROM ({{=it._query}}) _cdb_formula_nulls WHERE {{=it._column}} IS NULL) AS nulls_count',
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'FROM ({{=it._query}}) _cdb_formula'
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].join('\n'));
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var VALID_OPERATIONS = {
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count: true,
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avg: true,
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sum: true,
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min: true,
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max: true
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};
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var TYPE = 'formula';
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/**
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{
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type: 'formula',
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options: {
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column: 'name',
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operation: 'count' // count, sum, avg
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}
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}
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*/
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function Formula(query, options) {
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if (!_.isString(options.operation)) {
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throw new Error('Formula expects `operation` in widget options');
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}
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if (!VALID_OPERATIONS[options.operation]) {
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throw new Error("Formula does not support '" + options.operation + "' operation");
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}
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if (options.operation !== 'count' && !_.isString(options.column)) {
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throw new Error('Formula expects `column` in widget options');
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}
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BaseWidget.apply(this);
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this.query = query;
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this.column = options.column || '1';
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this.operation = options.operation;
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}
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Formula.prototype = new BaseWidget();
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Formula.prototype.constructor = Formula;
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module.exports = Formula;
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Formula.prototype.sql = function(psql, override, callback) {
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if (!callback) {
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callback = override;
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override = {};
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}
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var _query = this.query;
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var formulaSql = formulaQueryTpl({
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_query: _query,
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_operation: this.operation,
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_column: this.column
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});
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debug(formulaSql);
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return callback(null, formulaSql);
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};
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Formula.prototype.format = function(result) {
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var formattedResult = {
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operation: this.operation,
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result: 0,
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nulls: 0
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};
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if (result.rows.length) {
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formattedResult.operation = this.operation;
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formattedResult.result = result.rows[0].result;
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formattedResult.nulls = result.rows[0].nulls_count;
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}
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return formattedResult;
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};
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Formula.prototype.getType = function() {
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return TYPE;
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};
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Formula.prototype.toString = function() {
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return JSON.stringify({
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_type: TYPE,
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_query: this.query,
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_column: this.column,
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_operation: this.operation
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});
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};
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