Handling Dynamic Queries (cant scan into struct)
When using go-pg where the structure of queries is static - querying/scanning directly into a known struct works like a dream. But, I am struggling to handle dynamic queries - ones where there is no struct to scan into.
For example, depending on some run time parameters - queries could look like:
select foo from table
or it could be
select foo,bar,baz from table1
or
select x,y,z from table2
I've been trying to figure out how to use load the results into a map. The code below throws an error "invalid character '' looking for beginning of value"
m := make(map[string]interface{})
_,err:=db.Query(&m, "select foo,bar from table1")
if err!=nil{
fmt.Println(err)
}
I'm just starting to learn go - and am totally lost. Any tips on how to handle dynamic queries
go go-pg
edited Nov 23 '18 at 7:46
Flimzy
38.2k96597
asked Nov 22 '18 at 16:56
user163757user163757
3,66372339
add a comment |
When using go-pg where the structure of queries is static - querying/scanning directly into a known struct works like a dream. But, I am struggling to handle dynamic queries - ones where there is no struct to scan into.
For example, depending on some run time parameters - queries could look like:
select foo from table
or it could be
select foo,bar,baz from table1
or
select x,y,z from table2
I've been trying to figure out how to use load the results into a map. The code below throws an error "invalid character '' looking for beginning of value"
m := make(map[string]interface{})
_,err:=db.Query(&m, "select foo,bar from table1")
if err!=nil{
fmt.Println(err)
}
I'm just starting to learn go - and am totally lost. Any tips on how to handle dynamic queries
go go-pg
edited Nov 23 '18 at 7:46
Flimzy
38.2k96597
asked Nov 22 '18 at 16:56
user163757user163757
3,66372339
add a comment |
When using go-pg where the structure of queries is static - querying/scanning directly into a known struct works like a dream. But, I am struggling to handle dynamic queries - ones where there is no struct to scan into.
For example, depending on some run time parameters - queries could look like:
select foo from table
or it could be
select foo,bar,baz from table1
or
select x,y,z from table2
I've been trying to figure out how to use load the results into a map. The code below throws an error "invalid character '' looking for beginning of value"
m := make(map[string]interface{})
_,err:=db.Query(&m, "select foo,bar from table1")
if err!=nil{
fmt.Println(err)
}
I'm just starting to learn go - and am totally lost. Any tips on how to handle dynamic queries
go go-pg
edited Nov 23 '18 at 7:46
Flimzy
38.2k96597
asked Nov 22 '18 at 16:56
user163757user163757
3,66372339
When using go-pg where the structure of queries is static - querying/scanning directly into a known struct works like a dream. But, I am struggling to handle dynamic queries - ones where there is no struct to scan into.
For example, depending on some run time parameters - queries could look like:
select foo from table
or it could be
select foo,bar,baz from table1
or
select x,y,z from table2
I've been trying to figure out how to use load the results into a map. The code below throws an error "invalid character '' looking for beginning of value"
m := make(map[string]interface{})
_,err:=db.Query(&m, "select foo,bar from table1")
if err!=nil{
fmt.Println(err)
}
I'm just starting to learn go - and am totally lost. Any tips on how to handle dynamic queries
go go-pg
go go-pg
edited Nov 23 '18 at 7:46
Flimzy
38.2k96597
asked Nov 22 '18 at 16:56
user163757user163757
3,66372339
edited Nov 23 '18 at 7:46
Flimzy
38.2k96597
asked Nov 22 '18 at 16:56
user163757user163757
3,66372339
edited Nov 23 '18 at 7:46
Flimzy
38.2k96597
edited Nov 23 '18 at 7:46
Flimzy
38.2k96597
edited Nov 23 '18 at 7:46
Flimzy
38.2k96597
38.2k96597
asked Nov 22 '18 at 16:56
user163757user163757
3,66372339
asked Nov 22 '18 at 16:56
user163757user163757
3,66372339
asked Nov 22 '18 at 16:56
user163757user163757
3,66372339
3,66372339
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
You can achieve this by first scanning the database row values into a slice and subsequently building a map holding the values of the row.
Here is an example where the query results are scanned into an slice of pointers to variables of type interface{}.
sql := "select foo,bar from table1"
rows, err := db.Query(sql)
columns, err := rows.Columns()
// for each database row / record, a map with the column names and row values is added to the allMaps slice
var allMaps map[string]interface{}
for rows.Next() {
values := make(interface{}, len(columns))
pointers := make(interface{}, len(columns))
for i,_ := range values {
pointers[i] = &values[i]
}
err := rows.Scan(pointers...)
resultMap := make(map[string]interface{})
for i,val := range values {
fmt.Printf("Adding key=%s val=%vn", columns[i], val)
resultMap[columns[i]] = val
}
allMaps = append(allMaps, resultMap)
}
For brevity, no error checking is performed on any errors.
answered Nov 22 '18 at 23:46
Alexander van TrijffelAlexander van Trijffel
2,08111925
i had to switch from go-pg to database/sql with lib/pq and this works perfect.
– user163757
Nov 25 '18 at 0:21
You can also consider to use sqlx instead of database/sql for more functionality jmoiron.github.io/sqlx
– Alexander van Trijffel
Nov 25 '18 at 12:40
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
You can achieve this by first scanning the database row values into a slice and subsequently building a map holding the values of the row.
Here is an example where the query results are scanned into an slice of pointers to variables of type interface{}.
sql := "select foo,bar from table1"
rows, err := db.Query(sql)
columns, err := rows.Columns()
// for each database row / record, a map with the column names and row values is added to the allMaps slice
var allMaps map[string]interface{}
for rows.Next() {
values := make(interface{}, len(columns))
pointers := make(interface{}, len(columns))
for i,_ := range values {
pointers[i] = &values[i]
}
err := rows.Scan(pointers...)
resultMap := make(map[string]interface{})
for i,val := range values {
fmt.Printf("Adding key=%s val=%vn", columns[i], val)
resultMap[columns[i]] = val
}
allMaps = append(allMaps, resultMap)
}
For brevity, no error checking is performed on any errors.
answered Nov 22 '18 at 23:46
Alexander van TrijffelAlexander van Trijffel
2,08111925
i had to switch from go-pg to database/sql with lib/pq and this works perfect.
– user163757
Nov 25 '18 at 0:21
You can also consider to use sqlx instead of database/sql for more functionality jmoiron.github.io/sqlx
– Alexander van Trijffel
Nov 25 '18 at 12:40
add a comment |
You can achieve this by first scanning the database row values into a slice and subsequently building a map holding the values of the row.
Here is an example where the query results are scanned into an slice of pointers to variables of type interface{}.
sql := "select foo,bar from table1"
rows, err := db.Query(sql)
columns, err := rows.Columns()
// for each database row / record, a map with the column names and row values is added to the allMaps slice
var allMaps map[string]interface{}
for rows.Next() {
values := make(interface{}, len(columns))
pointers := make(interface{}, len(columns))
for i,_ := range values {
pointers[i] = &values[i]
}
err := rows.Scan(pointers...)
resultMap := make(map[string]interface{})
for i,val := range values {
fmt.Printf("Adding key=%s val=%vn", columns[i], val)
resultMap[columns[i]] = val
}
allMaps = append(allMaps, resultMap)
}
For brevity, no error checking is performed on any errors.
answered Nov 22 '18 at 23:46
Alexander van TrijffelAlexander van Trijffel
2,08111925
i had to switch from go-pg to database/sql with lib/pq and this works perfect.
– user163757
Nov 25 '18 at 0:21
You can also consider to use sqlx instead of database/sql for more functionality jmoiron.github.io/sqlx
– Alexander van Trijffel
Nov 25 '18 at 12:40
add a comment |
You can achieve this by first scanning the database row values into a slice and subsequently building a map holding the values of the row.
Here is an example where the query results are scanned into an slice of pointers to variables of type interface{}.
sql := "select foo,bar from table1"
rows, err := db.Query(sql)
columns, err := rows.Columns()
// for each database row / record, a map with the column names and row values is added to the allMaps slice
var allMaps map[string]interface{}
for rows.Next() {
values := make(interface{}, len(columns))
pointers := make(interface{}, len(columns))
for i,_ := range values {
pointers[i] = &values[i]
}
err := rows.Scan(pointers...)
resultMap := make(map[string]interface{})
for i,val := range values {
fmt.Printf("Adding key=%s val=%vn", columns[i], val)
resultMap[columns[i]] = val
}
allMaps = append(allMaps, resultMap)
}
For brevity, no error checking is performed on any errors.
answered Nov 22 '18 at 23:46
Alexander van TrijffelAlexander van Trijffel
2,08111925
You can achieve this by first scanning the database row values into a slice and subsequently building a map holding the values of the row.
Here is an example where the query results are scanned into an slice of pointers to variables of type interface{}.
sql := "select foo,bar from table1"
rows, err := db.Query(sql)
columns, err := rows.Columns()
// for each database row / record, a map with the column names and row values is added to the allMaps slice
var allMaps map[string]interface{}
for rows.Next() {
values := make(interface{}, len(columns))
pointers := make(interface{}, len(columns))
for i,_ := range values {
pointers[i] = &values[i]
}
err := rows.Scan(pointers...)
resultMap := make(map[string]interface{})
for i,val := range values {
fmt.Printf("Adding key=%s val=%vn", columns[i], val)
resultMap[columns[i]] = val
}
allMaps = append(allMaps, resultMap)
}
For brevity, no error checking is performed on any errors.
answered Nov 22 '18 at 23:46
Alexander van TrijffelAlexander van Trijffel
2,08111925
answered Nov 22 '18 at 23:46
Alexander van TrijffelAlexander van Trijffel
2,08111925
answered Nov 22 '18 at 23:46
Alexander van TrijffelAlexander van Trijffel
2,08111925
answered Nov 22 '18 at 23:46
Alexander van TrijffelAlexander van Trijffel
2,08111925
2,08111925
i had to switch from go-pg to database/sql with lib/pq and this works perfect.
– user163757
Nov 25 '18 at 0:21
You can also consider to use sqlx instead of database/sql for more functionality jmoiron.github.io/sqlx
– Alexander van Trijffel
Nov 25 '18 at 12:40
add a comment |
i had to switch from go-pg to database/sql with lib/pq and this works perfect.
– user163757
Nov 25 '18 at 0:21
You can also consider to use sqlx instead of database/sql for more functionality jmoiron.github.io/sqlx
– Alexander van Trijffel
Nov 25 '18 at 12:40
i had to switch from go-pg to database/sql with lib/pq and this works perfect.
– user163757
Nov 25 '18 at 0:21
i had to switch from go-pg to database/sql with lib/pq and this works perfect.
– user163757
Nov 25 '18 at 0:21
You can also consider to use sqlx instead of database/sql for more functionality jmoiron.github.io/sqlx
– Alexander van Trijffel
Nov 25 '18 at 12:40
You can also consider to use sqlx instead of database/sql for more functionality jmoiron.github.io/sqlx
– Alexander van Trijffel
Nov 25 '18 at 12:40
add a comment |
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