/
cursor.go
56 lines (46 loc) · 1.05 KB
/
cursor.go
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package csvutil
import (
"fmt"
"gorm.io/gorm"
)
type Cursor[T any] struct {
DBconn *gorm.DB
Query string
FetchSize int
}
func NewCursor[T any](dbconn *gorm.DB, query string, fetchSize int) (*Cursor[T], error) {
cursor := &Cursor[T]{
DBconn: dbconn,
Query: query,
FetchSize: fetchSize,
}
// Start a transaction
cursor.DBconn = cursor.DBconn.Begin()
// Declare a cursor
if err := cursor.DBconn.Exec("DECLARE mycursor CURSOR FOR " + query).Error; err != nil {
return nil, err
}
return cursor, nil
}
func (cursor *Cursor[T]) FetchCursor() ([]T, error) {
holder := make([]T, 0)
stmt := fmt.Sprintf("FETCH %d FROM mycursor", cursor.FetchSize)
// Fetch the results
if err := cursor.DBconn.Raw(stmt).Scan(&holder).Error; err != nil {
return nil, err
}
return holder, nil
}
func (cursor *Cursor[T]) Close() error {
// Close the cursor
err := cursor.DBconn.Exec("CLOSE mycursor").Error
if err != nil {
return err
}
// Commit the transaction
err = cursor.DBconn.Commit().Error
if err != nil {
return err
}
return nil
}