go - Reading database rows into map and appending to a slice of maps -

i trying use maps , slice of maps store rows returned database query. in every iteration of rows.next() , in final slice of 1 same row query. seems problem related memory place being same store cols, yet not resolve until now.

what thing missing here:

the source code follows:

package main  import (     "database/sql"     _ "github.com/lib/pq"      "fmt"     "log"      "reflect" ) var mymap = make(map[string]interface{}) var myslice = make([]map[string]interface{}, 0)  func main(){     fmt.println("this go playground.")      // db connection-     db, err := sql.open("postgres", "user=postgres dbname=proj2-dbcruddb-dev password=12345 sslmode=disable")     if err != nil {         log.fatalln(err)     }     rows, err := db.query("select id, username, password userstable")     defer rows.close()     if err != nil {         log.fatal(err)     }      colnames, err := rows.columns()     if err != nil {         log.fatal(err)     }     cols := make([]interface{}, len(colnames))     colptrs := make([]interface{}, len(colnames))     := 0; < len(colnames); i++ {         colptrs[i] = &cols[i]     }      rows.next() {         err = rows.scan(colptrs...)         if err != nil {             log.fatal(err)         }         fmt.println("cols: ", cols)          i, col := range cols {             mymap[colnames[i]] = col         }         myslice = append(myslice, mymap)          // map         key, val := range mymap {             fmt.println("key:", key, "value:", val, "value type:", reflect.typeof(val))         }         fmt.println("mymap: ", mymap)         fmt.println("myslice: ", myslice)      }     fmt.println(myslice) } 

this because storing in slice pointer map rather copy of map.

from go maps in action:

map types reference types, pointers or slices...

since create map outside loop updates it, keep overwriting data in map new data , appending pointer same map slice each time. multiple copies of same thing in slice (being last record read table).

to handle, move var mymap = make(map[string]interface{}) for rows.next() loop new map create on each iteration , appended slice.