138 lines
3.8 KiB
JavaScript
138 lines
3.8 KiB
JavaScript
var BaseDataview = require('./base');
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var debug = require('debug')('windshaft:dataview:formula');
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const countInfinitiesQueryTpl = ctx => `
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SELECT count(1) FROM (${ctx._query}) __cdb_formula_infinities
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WHERE ${ctx._column} = 'infinity'::float OR ${ctx._column} = '-infinity'::float
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`;
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const countNansQueryTpl = ctx => `
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SELECT count(1) FROM (${ctx._query}) __cdb_formula_nans
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WHERE ${ctx._column} = 'NaN'::float
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`;
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const filterOutSpecialNumericValuesTpl = ctx => `
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WHERE
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${ctx._column} != 'infinity'::float
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AND
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${ctx._column} != '-infinity'::float
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AND
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${ctx._column} != 'NaN'::float
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`;
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const formulaQueryTpl = ctx => `
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SELECT
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${ctx._operation}(${ctx._column}) AS result,
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(SELECT count(1) FROM (${ctx._query}) _cdb_formula_nulls WHERE ${ctx._column} IS NULL) AS nulls_count
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${ctx._isFloatColumn ? `,(${countInfinitiesQueryTpl(ctx)}) AS infinities_count` : ''}
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${ctx._isFloatColumn ? `,(${countNansQueryTpl(ctx)}) AS nans_count` : ''}
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FROM (${ctx._query}) __cdb_formula
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${ctx._isFloatColumn && ctx._operation !== 'count' ? `${filterOutSpecialNumericValuesTpl(ctx)}` : ''}
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`;
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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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module.exports = class Formula extends BaseDataview {
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constructor (query, options = {}, queries = {}) {
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if (typeof options.operation !== 'string') {
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throw new Error(`Formula expects 'operation' in dataview 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' && typeof options.column !== 'string') {
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throw new Error(`Formula expects 'column' in dataview options`);
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}
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this.query = query;
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this.queries = queries;
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this.column = options.column || '1';
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this.operation = options.operation;
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this._isFloatColumn = null;
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}
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sql (psql, override, callback) {
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var self = this;
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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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if (this._isFloatColumn === null) {
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this._isFloatColumn = false;
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this.getColumnType(psql, this.column, this.queries.no_filters, function (err, type) {
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if (!err && !!type) {
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self._isFloatColumn = type.float;
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}
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self.sql(psql, override, callback);
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});
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return null;
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}
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var formulaSql = formulaQueryTpl({
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_isFloatColumn: this._isFloatColumn,
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_query: this.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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format (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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nans: 0,
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infinities: 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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formattedResult.nans = result.rows[0].nans_count;
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formattedResult.infinities = result.rows[0].infinities_count;
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}
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return formattedResult;
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}
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getType () {
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return TYPE;
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};
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toString () {
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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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}
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