sqlpad/models/QueryResult.js

Web app for writing and running SQL queries and visualizing the results. Supports Postgres, MySQL, SQL Server, Crate and Vertica.

/*
    Unlike other models, QueryResult does not have a db layer built in
    It is more a formalization of how the result of a query should be
    represented regardless of the driver behind things.
    Anything that handles a query result (be it a cache file, grid, chart)
    should expect the data to be in this format
*/
var _ = require('lodash')
var uuid = require('uuid')

function isNumberLike(n) {
  return !isNaN(parseFloat(n)) && isFinite(n)
}

function QueryResult() {
  this.id = uuid.v1() // each result has unique id. used to determine whether results changed in React
  this.cacheKey = null
  this.startTime = null
  this.stopTime = null
  this.queryRunTime = null
  this.processedInitialHeader = false
  this.fields = [] // array of field names
  this.incomplete = false // signals whether results were truncated due to MAX_ROWS
  this.meta = {
    /*
    fieldname: {
        datatype: '',       // date, number or string
        max: 0,             // if datatype is a number or date
        min: 0,             // if datatype is number or date
        maxValueLength: 0   // populated if string
    }
    */
  }
  this.rows = [] // array of row objects [{col1: value, col2: value}]
}

QueryResult.prototype.timerStart = function() {
  this.startTime = new Date()
  this.stopTime = undefined
}

QueryResult.prototype.timerStop = function() {
  this.stopTime = new Date()
  this.queryRunTime = this.stopTime - this.startTime
}

QueryResult.prototype.addRows = function QueryResultAddRows(rows) {
  rows.forEach(function(row) {
    this.addRow(row)
  }, this)
}

QueryResult.prototype.addRow = function QueryResultAddRow(row) {
  this.rows.push(row)
  _.forOwn(
    row,
    function(value, key) {
      // if this is first row added, record fields in fields array
      if (!this.processedInitialHeader) {
        this.fields.push(key)
      }

      if (!this.meta[key]) {
        this.meta[key] = {
          datatype: null,
          max: null,
          min: null,
          maxValueLength: 0
        }
      }

      // if there is no value none of what follows will be helpful
      if (value == null) return

      // if we don't have a data type and we have a value yet lets try and figure it out
      if (!this.meta[key].datatype) {
        if (_.isDate(value)) this.meta[key].datatype = 'date'
        if (_.isNumber(value)) this.meta[key].datatype = 'number'
        else if (isNumberLike(value)) {
          // BIGINT and aggregate results sometimes come in as strings depending on db driver
          // if they contain a numeric value we want to treat them as a numeric
          this.meta[key].datatype = 'number'
        } else if (_.isString(value)) {
          this.meta[key].datatype = 'string'
          if (this.meta[key].maxValueLength < value.length) {
            this.meta[key].maxValueLength = value.length
          }
        }
      }

      // if the datatype is number-like,
      // we should check to see if it ever changes to a string
      // this is hacky, but sometimes data will be
      // a mix of number-like and strings that aren't number like
      // in the event that we get some data that's NOT NUMBER LIKE,
      // then we should *really* be recording this as string
      // also - if first character is 0 revert back to string
      if (this.meta[key].datatype === 'number' && _.isString(value)) {
        if (!isNumberLike(value) || value[0] === '0') {
          this.meta[key].datatype = 'string'
          this.meta[key].max = null
          this.meta[key].min = null
        }
      }

      // if we have a value and are dealing with a number or date, we should get min and max
      if (this.meta[key].datatype === 'number' && isNumberLike(value)) {
        value = Number(value)
        // if we haven't yet defined a max and this row contains a number
        if (!this.meta[key].max) this.meta[key].max = value
        else if (value > this.meta[key].max) {
          // otherwise this field in this row contains a number, and we should see if its bigger
          this.meta[key].max = value
        }
        // then do the same thing for min
        if (!this.meta[key].min) this.meta[key].min = value
        else if (value < this.meta[key].min) this.meta[key].min = value
      }

      if (this.meta[key].datatype === 'date' && _.isDate(value)) {
        // if we haven't yet defined a max and this row contains a number
        if (!this.meta[key].max) this.meta[key].max = value
        else if (value > this.meta[key].max) {
          // otherwise this field in this row contains a number, and we should see if its bigger
          this.meta[key].max = value
        }
        // then do the same thing for min
        if (!this.meta[key].min) this.meta[key].min = value
        else if (value < this.meta[key].min) this.meta[key].min = value
      }
    }.bind(this)
  )

  // if we haven't processed the header yet we have now
  if (!this.processedInitialHeader) {
    this.processedInitialHeader = true
  }
}

module.exports = QueryResult