forked from opengaussexamples/examples
109 lines
2.5 KiB
Go
109 lines
2.5 KiB
Go
package main
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import (
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"context"
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"database/sql"
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"fmt"
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"gitee.com/chentanyang/ogx"
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"gitee.com/chentanyang/ogx/dialect/ogdialect"
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"gitee.com/chentanyang/ogx/extra/ogxdebug"
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_ "gitee.com/opengauss/openGauss-connector-go-pq"
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)
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type Item struct {
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ID int64 `ogx:",pk,autoincrement"`
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Children []Item `ogx:"m2m:item_to_items,join:Item=Child"`
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}
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type ItemToItem struct {
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ItemID int64 `ogx:",pk"`
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Item *Item `ogx:"rel:belongs-to,join:item_id=id"`
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ChildID int64 `ogx:",pk"`
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Child *Item `ogx:"rel:belongs-to,join:child_id=id"`
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}
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func main() {
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ctx := context.Background()
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connStr := "host=192.168.20.40 port=26000 user=cuih password=Gauss@123 dbname=test sslmode=disable"
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opengaussdb, err := sql.Open("opengauss", connStr)
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if err != nil {
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panic(err)
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}
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db := ogx.NewDB(opengaussdb, ogdialect.New())
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defer db.Close()
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db.AddQueryHook(ogxdebug.NewQueryHook(ogxdebug.WithVerbose(true)))
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// Register many to many model so ogx can better recognize m2m relation.
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// This should be done before you use the model for the first time.
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db.RegisterModel((*ItemToItem)(nil))
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if err := createSchema(ctx, db, (*Item)(nil), (*ItemToItem)(nil)); err != nil {
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panic(err)
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}
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defer func() {
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_ = dropSchema(ctx, db, (*Item)(nil), (*ItemToItem)(nil))
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}()
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item1 := new(Item)
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if err := db.NewSelect().
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Model(item1).
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Relation("Children").
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Order("item.id ASC").
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Where("id = 1").
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Scan(ctx); err != nil {
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panic(err)
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}
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item2 := new(Item)
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if err := db.NewSelect().
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Model(item2).
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Relation("Children").
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Order("item.id ASC").
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Where("id = 2").
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Scan(ctx); err != nil {
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panic(err)
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}
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fmt.Println("item1", item1.ID, "children", item1.Children[0].ID, item1.Children[1].ID)
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fmt.Println("item2", item2.ID, "children", item2.Children[0].ID, item2.Children[1].ID)
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}
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func createSchema(ctx context.Context, db *ogx.DB, models ...interface{}) error {
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for _, model := range models {
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if err := db.ResetModel(ctx, model); err != nil {
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return err
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}
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}
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values := []interface{}{
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&Item{ID: 1},
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&Item{ID: 2},
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&Item{ID: 3},
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&Item{ID: 4},
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&ItemToItem{ItemID: 1, ChildID: 2},
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&ItemToItem{ItemID: 1, ChildID: 3},
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&ItemToItem{ItemID: 2, ChildID: 3},
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&ItemToItem{ItemID: 2, ChildID: 4},
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}
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for _, value := range values {
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if _, err := db.NewInsert().Model(value).Exec(ctx); err != nil {
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return err
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}
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}
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return nil
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}
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func dropSchema(ctx context.Context, db *ogx.DB, models ...interface{}) error {
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for _, model := range models {
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if _, err := db.NewDropTable().Model(model).IfExists().Cascade().Exec(ctx); err != nil {
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return err
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}
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}
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return nil
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}
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