Copy data between tables and files

PostgreSQL allows to efficiently copy data between tables and files using COPY TO and COPY FROM commands.

COPY TO

To copy data from a table to an io.Writer:

import "github.com/uptrace/bun/driver/pgdriver"
conn, err := db.Conn(ctx)
if err != nil {
    panic(err)
}
defer conn.Close()
var buf bytes.Buffer
res, err := pgdriver.CopyTo(ctx, conn, &buf, "COPY table_name TO STDOUT")
if err != nil {
    panic(err)
}
fmt.Println(buf.String())

COPY FROM

To copy data from an io.Reader to a table:

import "github.com/uptrace/bun/driver/pgdriver"
conn, err := db.Conn(ctx)
if err != nil {
    panic(err)
}
defer conn.Close()
file, err := os.Open("data.csv")
if err != nil {
    panic(err)
}
res, err := pgdriver.CopyFrom(ctx, conn, file, "COPY table_name FROM STDIN")
if err != nil {
    panic(err)
}