Insert or update: MariaDB and DuckDB
Every file of the MariaDB and DuckDB versions side by side, with the lines that differ marked.
Configuration
sgl.yamldiffers
MariaDB
DuckDB
1
version: 11
version: 12
2
3
databases:3
databases:4
- name: stock4
- name: stock5
dialect: mysql5
dialect: duckdb6
migrations: db/migrations6
migrations: db/migrations7
queries: db/queries7
queries: db/queries8
go:8
go:9
package: store9
package: store10
out: internal/store10
out: internal/storeMigrations
db/migrations/0001_stock.up.sqldiffers
MariaDB
DuckDB
1
CREATE TABLE stock (1
CREATE TABLE stock (2
item VARCHAR(50) NOT NULL PRIMARY KEY,2
item VARCHAR PRIMARY KEY,3
quantity INT NOT NULL,3
quantity INTEGER NOT NULL,4
deliveries INT NOT NULL DEFAULT 04
deliveries INTEGER NOT NULL DEFAULT 05
);5
);db/migrations/0001_stock.down.sqlidentical
MariaDB
DuckDB
1
DROP TABLE stock;1
DROP TABLE stock;Queries
ReceiveDeliverydiffers
MariaDB · db/queries/stock.sql
DuckDB · db/queries/stock.sql
1
-- sgl.query(ReceiveDelivery, execrows)1
-- sgl.query(ReceiveDelivery, one)2
INSERT INTO stock (item, quantity, deliveries) VALUES (?, ?, 1)2
INSERT INTO stock (item, quantity, deliveries) VALUES ($1, $2, 1)3
ON DUPLICATE KEY UPDATE3
ON CONFLICT (item) DO UPDATE SET4
quantity = quantity + VALUES(quantity),4
quantity = stock.quantity + excluded.quantity,5
deliveries = deliveries + 1;5
deliveries = stock.deliveries + 16
RETURNING item, quantity, deliveries;GetStockonly MariaDB
MariaDB · db/queries/stock.sql
DuckDB · not in this version
1
-- sgl.query(GetStock, one)2
SELECT item, quantity, deliveries FROM stock WHERE item = ?;AddItemdiffers
MariaDB · db/queries/stock.sql
DuckDB · db/queries/stock.sql
1
-- sgl.query(AddItem, execrows)1
-- sgl.query(AddItem, execrows)2
INSERT INTO stock (item, quantity) VALUES (?, 0)2
INSERT INTO stock (item, quantity) VALUES ($1, 0)3
ON DUPLICATE KEY UPDATE item = item;3
ON CONFLICT (item) DO NOTHING;ListStockidentical
MariaDB · db/queries/stock.sql
DuckDB · db/queries/stock.sql
1
-- sgl.query(ListStock, many)1
-- sgl.query(ListStock, many)2
SELECT item, quantity, deliveries FROM stock ORDER BY item;2
SELECT item, quantity, deliveries FROM stock ORDER BY item;What sgl generates
ReceiveDeliverydiffers
MariaDB
DuckDB
1
func (queries *Queries) ReceiveDelivery(ctx context.Context, params ReceiveDeliveryParams) (int64, error)1
func (queries *Queries) ReceiveDelivery(ctx context.Context, params ReceiveDeliveryParams) (ReceiveDeliveryRow, error)2
2
3
type ReceiveDeliveryParams struct {3
type ReceiveDeliveryParams struct {4
Item string4
Item string5
Quantity int325
Quantity int326
}6
}7
8
type ReceiveDeliveryRow struct {9
Item string `json:"item"`10
Quantity int32 `json:"quantity"`11
Deliveries int32 `json:"deliveries"`12
}GetStockonly MariaDB
MariaDB
DuckDB · not in this version
1
func (queries *Queries) GetStock(ctx context.Context, item string) (GetStockRow, error)2
3
type GetStockRow struct {4
Item string `json:"item"`5
Quantity int32 `json:"quantity"`6
Deliveries int32 `json:"deliveries"`7
}AddItemidentical
MariaDB
DuckDB
1
func (queries *Queries) AddItem(ctx context.Context, item string) (int64, error)1
func (queries *Queries) AddItem(ctx context.Context, item string) (int64, error)ListStockidentical
MariaDB
DuckDB
1
func (queries *Queries) ListStock(ctx context.Context) ([]ListStockRow, error)1
func (queries *Queries) ListStock(ctx context.Context) ([]ListStockRow, error)2
2
3
type ListStockRow struct {3
type ListStockRow struct {4
Item string `json:"item"`4
Item string `json:"item"`5
Quantity int32 `json:"quantity"`5
Quantity int32 `json:"quantity"`6
Deliveries int32 `json:"deliveries"`6
Deliveries int32 `json:"deliveries"`7
}7
}The program
example.godiffers
MariaDB
DuckDB
1
package main1
package main2
2
3
import (3
import (4
"context"4
"context"5
"database/sql"5
"database/sql"6
"fmt"6
"fmt"7
"io"7
"io"8
8
9
"seagull.sh/seagull/examples/mysql/021_upserts/internal/store"9
"seagull.sh/seagull/examples/duckdb/021_upserts/internal/store"10
)10
)11
11
12
// run books three deliveries into the stock table, two of them for the same item, then12
// run books three deliveries into the stock table, two of them for the same item, then13
// adds two items only if they are new, and prints the stock that results.13
// adds two items only if they are new, and prints the stock that results.14
//14
//15
// Takes database (*sql.DB) which is a migrated database.15
// Takes database (*sql.DB) which is a migrated database.16
// Takes output (io.Writer) which receives each upsert's outcome and the final stock.16
// Takes output (io.Writer) which receives each upsert's outcome and the final stock.17
//17
//18
// Returns error when a query fails.18
// Returns error when a query fails.19
func run(ctx context.Context, database *sql.DB, output io.Writer) error {19
func run(ctx context.Context, database *sql.DB, output io.Writer) error {20
queries := store.New(database)20
queries := store.New(database)21
21
22
// ReceiveDelivery inserts a new item, or adds to the quantity of one already in stock.22
// ReceiveDelivery inserts a new item, or adds to the quantity of one already in stock.23
// VALUES(quantity) is the value the INSERT tried to write, so the parameters stay plain23
// excluded.quantity is the value the INSERT tried to write, so the parameters stay plain24
// Item and Quantity fields. MySQL 8.0.19 and later also accept a row alias, VALUES (?,24
// Item and Quantity fields.25
// ?, 1) AS new with new.quantity, and deprecate VALUES(); MariaDB accepts only VALUES(),26
// so the example keeps to it.27
//28
// MySQL has no RETURNING, so the method is execrows, and MySQL's count says what29
// happened: 1 for a row inserted, 2 for a row updated. GetStock then reads the row as it30
// ended up.31
deliveries := []store.ReceiveDeliveryParams{25
deliveries := []store.ReceiveDeliveryParams{32
{Item: "cod", Quantity: 10},26
{Item: "cod", Quantity: 10},33
{Item: "potatoes", Quantity: 40},27
{Item: "potatoes", Quantity: 40},34
{Item: "cod", Quantity: 5},28
{Item: "cod", Quantity: 5},35
}29
}36
for _, delivery := range deliveries {30
for _, delivery := range deliveries {37
affected, err := queries.ReceiveDelivery(ctx, delivery)31
row, err := queries.ReceiveDelivery(ctx, delivery)38
if err != nil {32
if err != nil {39
return fmt.Errorf("receiving %s: %w", delivery.Item, err)33
return fmt.Errorf("receiving %s: %w", delivery.Item, err)40
}34
}41
row, err := queries.GetStock(ctx, delivery.Item)35
fmt.Fprintf(output, "%-8s delivery %d: +%d, now %d in stock\n",42
if err != nil {36
row.Item, row.Deliveries, delivery.Quantity, row.Quantity)43
return fmt.Errorf("reading %s: %w", delivery.Item, err)44
}45
outcome := "inserted"46
if affected == 2 {47
outcome = "updated"48
}49
fmt.Fprintf(output, "%-8s delivery %d: +%d, now %d in stock (%s)\n",50
row.Item, row.Deliveries, delivery.Quantity, row.Quantity, outcome)51
}37
}52
38
53
// AddItem sets item = item on a duplicate, which changes nothing, so MySQL counts 039
// AddItem uses DO NOTHING, and execrows reports whether the row went in: 1 for a new54
// rows: execrows reports 1 for a new item and 0 when the item was already there. It is40
// item, 0 when the item was already there and the insert was skipped.55
// MySQL's form of ON CONFLICT DO NOTHING; INSERT IGNORE would also hide errors such as a56
// value too long for its column.57
for _, item := range []string{"peas", "cod"} {41
for _, item := range []string{"peas", "cod"} {58
added, err := queries.AddItem(ctx, item)42
added, err := queries.AddItem(ctx, item)59
if err != nil {43
if err != nil {60
return fmt.Errorf("adding %s: %w", item, err)44
return fmt.Errorf("adding %s: %w", item, err)61
}45
}62
if added == 0 {46
if added == 0 {63
fmt.Fprintf(output, "%s is already stocked, nothing changed\n", item)47
fmt.Fprintf(output, "%s is already stocked, nothing changed\n", item)64
continue48
continue65
}49
}66
fmt.Fprintf(output, "added %s with no stock yet\n", item)50
fmt.Fprintf(output, "added %s with no stock yet\n", item)67
}51
}68
52
69
stock, err := queries.ListStock(ctx)53
stock, err := queries.ListStock(ctx)70
if err != nil {54
if err != nil {71
return fmt.Errorf("listing stock: %w", err)55
return fmt.Errorf("listing stock: %w", err)72
}56
}73
for _, row := range stock {57
for _, row := range stock {74
fmt.Fprintf(output, "%-8s %2d\n", row.Item, row.Quantity)58
fmt.Fprintf(output, "%-8s %2d\n", row.Item, row.Quantity)75
}59
}76
return nil60
return nil77
}61
}