Handling Dynamic Queries (cant scan into struct)
up vote
0
down vote
favorite
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 at 7:46
Flimzy
36.9k96496
asked Nov 22 at 16:56
user163757
3,59872339
add a comment |
up vote
0
down vote
favorite
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 at 7:46
Flimzy
36.9k96496
asked Nov 22 at 16:56
user163757
3,59872339
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
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 at 7:46
Flimzy
36.9k96496
asked Nov 22 at 16:56
user163757
3,59872339
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 at 7:46
Flimzy
36.9k96496
asked Nov 22 at 16:56
user163757
3,59872339
edited Nov 23 at 7:46
Flimzy
36.9k96496
asked Nov 22 at 16:56
user163757
3,59872339
edited Nov 23 at 7:46
Flimzy
36.9k96496
edited Nov 23 at 7:46
Flimzy
36.9k96496
edited Nov 23 at 7:46
Flimzy
36.9k96496
36.9k96496
asked Nov 22 at 16:56
user163757
3,59872339
asked Nov 22 at 16:56
user163757
3,59872339
asked Nov 22 at 16:56
user163757
3,59872339
3,59872339
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
up vote
1
down vote
accepted
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 at 23:46
Alexander van Trijffel
2,05111925
i had to switch from go-pg to database/sql with lib/pq and this works perfect.
– user163757
Nov 25 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 at 12:40
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53435455%2fhandling-dynamic-queries-cant-scan-into-struct%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
1
down vote
accepted
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 at 23:46
Alexander van Trijffel
2,05111925
i had to switch from go-pg to database/sql with lib/pq and this works perfect.
– user163757
Nov 25 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 at 12:40
add a comment |
up vote
1
down vote
accepted
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 at 23:46
Alexander van Trijffel
2,05111925
i had to switch from go-pg to database/sql with lib/pq and this works perfect.
– user163757
Nov 25 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 at 12:40
add a comment |
up vote
1
down vote
accepted
up vote
1
down vote
accepted
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 at 23:46
Alexander van Trijffel
2,05111925
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 at 23:46
Alexander van Trijffel
2,05111925
answered Nov 22 at 23:46
Alexander van Trijffel
2,05111925
answered Nov 22 at 23:46
Alexander van Trijffel
2,05111925
answered Nov 22 at 23:46
Alexander van Trijffel
2,05111925
2,05111925
i had to switch from go-pg to database/sql with lib/pq and this works perfect.
– user163757
Nov 25 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 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 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 at 12:40
i had to switch from go-pg to database/sql with lib/pq and this works perfect.
– user163757
Nov 25 at 0:21
i had to switch from go-pg to database/sql with lib/pq and this works perfect.
– user163757
Nov 25 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 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 at 12:40
add a comment |
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Some of your past answers have not been well-received, and you're in danger of being blocked from answering.
Please pay close attention to the following guidance:
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53435455%2fhandling-dynamic-queries-cant-scan-into-struct%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
