README
¶
structql (SQL for GoLang data structures)
This library is compatible with Go 1.17+
Please refer to CHANGELOG.md if you encounter breaking changes.
Motivation
The primary aim of this library is to facilitate access to structured data through SQL queries. It is specifically tailored to transform Golang data structures using SQL syntax. The initial release of this library focuses on implementing the foundational features of SQL, laying the groundwork for more advanced functionalities in future updates
Introduction
Go struct transformation with SQL
- Basic Query
SQL := "SELECT ID, Name FROM `/` WHERE Status = 2"
query, err := structql.NewQuery(SQL, reflect.TypeOf(&Vendor{}), nil)
if err != nil {
log.Fatal(err)
}
result, err := query.Select(vendors)
if err != nil {
log.Fatal(err)
}
- Nested Query
SQL := "SELECT ProductID,Revenue FROM `/Products[Active=1]/Performance` WHERE Revenue > 100.0 "
query, err := structql.NewQuery(SQL, reflect.TypeOf(&Vendor{}), nil)
if err != nil {
log.Fatal(err)
}
result, err := query.Select(vendors)
if err != nil {
log.Fatal(err)
}
Querying data with database/sql
DSN Data Source Name
The structql driver accepts the following DSN
-
'structql://[localhost|cloudProvider$bucket]/[baseURI|folderPath][{options}]'
Where queryString can optionally configure the following option:
- key: access key id
- secret: access key secret
Usage
database/sql
package mypkg
import (
"context"
"database/sql"
_ "github.com/viant/structql/sql"
"log"
)
func Example() {
db, err := sql.Open("structql", "structql:///opt/local/testdata/")
if err != nil {
log.Fatal(err)
}
type Foo struct {
ID int
Name string
}
_, err = db.Exec("REGISTER TYPE Foo AS ?", &Foo{})
if err != nil {
log.Fatal(err)
}
rows, err := db.QueryContext(context.Background(), "SELECT id,name FROM Foo WHERE id IN(?, ?)", 1, 3)
if err != nil {
log.Fatal(err)
}
var foos []*Foo
for rows.Next() {
var foo Foo
err = rows.Scan(&foo.ID, &foo.Name)
if err != nil {
log.Fatal(err)
}
foos = append(foos, &foo)
}
}
### Go struct transformation with SQL
```go
package myPkg
import (
"github.com/viant/structql"
"log"
"reflect"
"time"
)
type (
Vendor struct {
ID int
Name string
Revenue float64
Status int
Products []*Product
}
Product struct {
ID int
Name string
Status int
Performance []*Performance
}
Performance struct {
ProductID int
Date time.Time
Quantity float64
Revenue float64
}
)
func ExampleQuery_Select() {
var vendors = []*Vendor{
{
ID: 1,
Name: "Vendor 1",
Products: []*Product{
{
ID: 1,
Status: 1,
Name: "Product 1",
Performance: []*Performance{
{
ProductID: 1,
Revenue: 13050,
Quantity: 124,
},
},
},
},
},
{
ID: 2,
Name: "Vendor 2",
Products: []*Product{
{
ID: 2,
Name: "Product 2",
Status: 1,
Performance: []*Performance{
{
ProductID: 2,
Revenue: 16050,
Quantity: 110,
},
},
},
{
ID: 7,
Name: "Product 7",
Status: 0,
Performance: []*Performance{
{
ProductID: 7,
Revenue: 160,
Quantity: 10,
},
},
},
},
},
{
ID: 3,
Name: "Vendor 3",
Products: []*Product{
{
ID: 3,
Name: "Product 3",
Status: 1,
Performance: []*Performance{
{
ProductID: 3,
Revenue: 11750,
Quantity: 143,
},
},
},
{
ID: 4,
Name: "Product 4",
Status: 1,
Performance: []*Performance{
{
ProductID: 4,
Revenue: 11,
Quantity: 1,
},
},
},
},
},
}
SQL := "SELECT ProductID,Revenue FROM `/Products[Active=1]/Performance` WHERE Revenue > 100.0 "
type Query1Output struct {
ProductID int
Revenue float64
}
query, err := structql.NewQuery(SQL, reflect.TypeOf(vendors), reflect.TypeOf(Query1Output{}))
if err != nil {
log.Fatal(err)
}
result, err := query.Select(vendors)
if err != nil {
log.Fatal(err)
}
}
Contributing to structql
structql is an open source project and contributors are welcome!
See TODO list
Credits and Acknowledgements
Library Author: Adrian Witas
Documentation
¶
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type Mapper ¶
type Mapper struct {
// contains filtered or unexported fields
}
Mapper represents struct mapper
type Node ¶
type Node struct {
IsLeaf bool
// contains filtered or unexported fields
}
Node represents a node
func (*Node) LeafOwnerType ¶
LeafOwnerType returns leaf type
type NodeVisitor ¶
NodeVisitor represents a node visitor (struct or leaf node)
type Query ¶
type Query struct {
Limit int
CompType reflect.Type
Binding *node.Binding
// contains filtered or unexported fields
}
Query represents a selector
func (*Query) Select ¶
Select returns selection result
Example ¶
package main
import (
"fmt"
"github.com/viant/structql"
"log"
"reflect"
"time"
)
type (
Vendor struct {
ID int
Name string
Revenue float64
Products []*Product
}
Product struct {
ID int
Name string
Status int
Performance []*Performance
}
Performance struct {
ProductID int
Date time.Time
Quantity float64
Revenue float64
}
)
func main() {
var vendors = []*Vendor{
{
ID: 1,
Name: "Vendor 1",
Products: []*Product{
{
ID: 1,
Status: 1,
Name: "Product 1",
Performance: []*Performance{
{
ProductID: 1,
Revenue: 13050,
Quantity: 124,
},
},
},
},
},
{
ID: 2,
Name: "Vendor 2",
Products: []*Product{
{
ID: 2,
Name: "Product 2",
Status: 1,
Performance: []*Performance{
{
ProductID: 2,
Revenue: 16050,
Quantity: 110,
},
},
},
{
ID: 7,
Name: "Product 7",
Status: 0,
Performance: []*Performance{
{
ProductID: 7,
Revenue: 160,
Quantity: 10,
},
},
},
},
},
{
ID: 3,
Name: "Vendor 3",
Products: []*Product{
{
ID: 3,
Name: "Product 3",
Status: 1,
Performance: []*Performance{
{
ProductID: 3,
Revenue: 11750,
Quantity: 143,
},
},
},
{
ID: 4,
Name: "Product 4",
Status: 1,
Performance: []*Performance{
{
ProductID: 4,
Revenue: 11,
Quantity: 1,
},
},
},
},
},
}
SQL := "SELECT ProductID,Revenue FROM `/Products[Active=1]/Performance` WHERE Revenue > 100.0 "
type Query1Output struct {
ProductID int
Revenue float64
}
query, err := structql.NewQuery(SQL, reflect.TypeOf(vendors), reflect.TypeOf(Query1Output{}))
if err != nil {
log.Fatal(err)
}
result, err := query.Select(vendors)
if err != nil {
log.Fatal(err)
}
fmt.Printf("%v\n", result)
}
Output:
func (*Query) StructType ¶ added in v0.2.2
StructType returns dest struct type
Source Files
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