• kdb+

  GoLang Table to Struct?

  Posted by ekallivrousis on March 18, 2022 at 12:00 am

  So im starting to learn GoLang and noticed theres a KDB package. https://pkg.go.dev/github.com/sv/kdbgo

  Im wondering if anyone here has experience and can help. Im trying to query a table and convert to an object the program knows about.

  ekallivrousis replied 8 months, 1 week ago 2 Members · 1 Reply
• 1 Reply

• 

  rahul_asati04

  Member

  March 20, 2022 at 12:00 am

  This site has a good example to insert and select data from kdb process.

  https://janrock.medium.com/kdb-golang-oanda-e9bec0570799

   

  Here is an updated example from that site to show selecting kdb data in go process and storing that in go structure.

   

  KDB  `trade`  table

   

  q)trade 
  time sym price 
  --------------------------------------- 
  2015.10.19D18:40:22.982760448 a 100 
  2009.02.21D21:21:02.534721216 b 200

   

   

  Go Code

   

  package main import ( "time" "fmt" kdb "github.com/sv/kdbgo" ) 
  // Go struct to store KDB table type trade struct { Ts time.Time Sym string Price int64 } 
  // Function to convert KDB data to GO struct 
  func tableToStruct(tbl kdb.Table) []trade {
  var data = []trade{} 
  rowCount := int(tbl.Data[0].Len()) 
  for i := 0; i < rowCount; i++ {
   rec := trade{
  Ts: tbl.Data[0].Index(i).(time.Time), 
  Sym: tbl.Data[1].Index(i).(string), 
  Price: tbl.Data[2].Index(i).(int64)
  } 
  data = append(data, rec) 
  }
  return data
  } 
  
  func main() { 
  con, err := kdb.DialKDB("localhost", 5000, "") 
  if err != nil { 
  fmt.Println("Failed to connect: %v", err) 
  }
  
  ktbl, err := con.Call("select time, sym, price from trade")
  if err != nil 
  { 
  fmt.Println("Query failed: %v", err) 
  return 
  }
  
  series := tableToStruct(ktbl.Data.(kdb.Table)) 
  for _, v := range series 
  { 
  fmt.Printf("Timestamp: %v | Sym: %v | Price: %v n", v.Ts, v.Sym, v.Price) 
  } 
  con.Close()
   }

   

  Go Output:

  $ go run go-kdb.go

  Timestamp: 2015-10-19 18:40:22.982760448 +0000 UTC | Sym: a | Price: 100

  Timestamp: 2009-02-21 21:21:02.534721216 +0000 UTC | Sym: b | Price: 200

   

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