go-sqlite3/_example/json/main.go

110 lines
1.9 KiB
Go

package main
import (
"context"
"database/sql"
_ "embed"
"fmt"
"log"
"strings"
_ "github.com/mattn/go-sqlite3"
"github.com/rocketlaunchr/dataframe-go"
"github.com/rocketlaunchr/dataframe-go/imports"
)
//go:embed iris.csv
var irisData string
func main() {
db, err := sql.Open("sqlite3", ":memory:")
if err != nil {
log.Fatal(err)
}
defer db.Close()
sqlStmt := `
create table iris (
sepal_length float,
sepal_width float,
petal_length float,
petal_width float,
class int);
`
_, err = db.Exec(sqlStmt)
if err != nil {
log.Printf("%q: %s\n", err, sqlStmt)
return
}
tx, err := db.Begin()
if err != nil {
log.Fatal(err)
}
stmt, err := tx.Prepare(`
insert into iris(
sepal_length, sepal_width, petal_length, petal_width, class)
values(?, ?, ?, ?, ?)
`)
if err != nil {
log.Fatal(err)
}
defer stmt.Close()
df, err := imports.LoadFromCSV(context.Background(), strings.NewReader(irisData))
if err != nil {
log.Fatal(err)
}
it := df.ValuesIterator(dataframe.ValuesOptions{
InitialRow: 0,
Step: 1,
DontReadLock: true,
})
df.Lock()
for {
row, vals, _ := it()
if row == nil {
break
}
_, err = stmt.Exec(
vals["sepal_length"],
vals["sepal_width"],
vals["petal_length"],
vals["petal_width"],
vals["class"],
)
if err != nil {
log.Fatal(err)
}
}
df.Unlock()
tx.Commit()
rows, err := db.Query(`select
json_object(
'sepal_length', sepal_length,
'sepal_width', sepal_width,
'petal_length', petal_length,
'petal_width', petal_width,
'class', class
) from iris
`)
if err != nil {
log.Fatal(err)
}
defer rows.Close()
for rows.Next() {
var r string
err = rows.Scan(&r)
if err != nil {
log.Fatal(err)
}
fmt.Println(r)
}
err = rows.Err()
if err != nil {
log.Fatal(err)
}
}