Insert or update: CockroachDB and MariaDB
Every file of the CockroachDB and MariaDB versions side by side, with the lines that differ marked. 3 parameter or column types differ in Go.
Configuration
sgl.yamldiffers
CockroachDB
MariaDB
1
version: 11
version: 12
2
3
databases:3
databases:4
- name: stock4
- name: stock5
dialect: postgres5
dialect: mysql6
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/store11
driver: database/sql12
migrate:13
dsn: ${env:DATABASE_URL}Migrations
db/migrations/0001_stock.up.sqldiffers
CockroachDB
MariaDB
1
CREATE TABLE stock (1
CREATE TABLE stock (2
item TEXT PRIMARY KEY,2
item VARCHAR(50) NOT NULL PRIMARY KEY,3
quantity BIGINT NOT NULL,3
quantity INT NOT NULL,4
deliveries BIGINT NOT NULL DEFAULT 04
deliveries INT NOT NULL DEFAULT 05
);5
);db/migrations/0001_stock.down.sqlidentical
CockroachDB
MariaDB
1
DROP TABLE stock;1
DROP TABLE stock;Queries
ReceiveDeliverydiffers
CockroachDB · db/queries/stock.sql
MariaDB · db/queries/stock.sql
1
-- sgl.query(ReceiveDelivery, one)1
-- sgl.query(ReceiveDelivery, execrows)2
INSERT INTO stock (item, quantity, deliveries) VALUES ($1, $2, 1)2
INSERT INTO stock (item, quantity, deliveries) VALUES (?, ?, 1)3
ON CONFLICT (item) DO UPDATE SET3
ON DUPLICATE KEY UPDATE4
quantity = stock.quantity + EXCLUDED.quantity,4
quantity = quantity + VALUES(quantity),5
deliveries = stock.deliveries + 15
deliveries = deliveries + 1;6
RETURNING item, quantity, deliveries;AddItemdiffers
CockroachDB · db/queries/stock.sql
MariaDB · db/queries/stock.sql
1
-- sgl.query(AddItem, execrows)1
-- sgl.query(AddItem, execrows)2
INSERT INTO stock (item, quantity) VALUES ($1, 0)2
INSERT INTO stock (item, quantity) VALUES (?, 0)3
ON CONFLICT (item) DO NOTHING;3
ON DUPLICATE KEY UPDATE item = item;ListStockidentical
CockroachDB · db/queries/stock.sql
MariaDB · 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;GetStockonly MariaDB
CockroachDB · not in this version
MariaDB · db/queries/stock.sql
1
-- sgl.query(GetStock, one)2
SELECT item, quantity, deliveries FROM stock WHERE item = ?;What sgl generates
ReceiveDeliverydiffers
CockroachDB
MariaDB
1
func (queries *Queries) ReceiveDelivery(ctx context.Context, params ReceiveDeliveryParams) (ReceiveDeliveryRow, error)1
func (queries *Queries) ReceiveDelivery(ctx context.Context, params ReceiveDeliveryParams) (int64, error)2
2
3
type ReceiveDeliveryParams struct {3
type ReceiveDeliveryParams struct {4
Item string4
Item string5
Quantity int645
Quantity int326
}7
8
type ReceiveDeliveryRow struct {9
Item string `json:"item"`10
Quantity int64 `json:"quantity"`11
Deliveries int64 `json:"deliveries"`12
}6
}AddItemidentical
CockroachDB
MariaDB
1
func (queries *Queries) AddItem(ctx context.Context, item string) (int64, error)1
func (queries *Queries) AddItem(ctx context.Context, item string) (int64, error)ListStockdiffers
CockroachDB
MariaDB
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 int64 `json:"quantity"`5
Quantity int32 `json:"quantity"`6
Deliveries int64 `json:"deliveries"`6
Deliveries int32 `json:"deliveries"`7
}7
}GetStockonly MariaDB
CockroachDB · not in this version
MariaDB
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
}The program
example.godiffers
CockroachDB
MariaDB
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/postgres/021_upserts/internal/store"9
"seagull.sh/seagull/examples/mysql/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
// EXCLUDED.quantity is the value the INSERT tried to write, so the parameters stay plain23
// VALUES(quantity) is the value the INSERT tried to write, so the parameters stay plain24
// Item and Quantity fields.24
// Item and Quantity fields. MySQL 8.0.19 and later also accept a row alias, VALUES (?,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.25
deliveries := []store.ReceiveDeliveryParams{31
deliveries := []store.ReceiveDeliveryParams{26
{Item: "cod", Quantity: 10},32
{Item: "cod", Quantity: 10},27
{Item: "potatoes", Quantity: 40},33
{Item: "potatoes", Quantity: 40},28
{Item: "cod", Quantity: 5},34
{Item: "cod", Quantity: 5},29
}35
}30
for _, delivery := range deliveries {36
for _, delivery := range deliveries {31
row, err := queries.ReceiveDelivery(ctx, delivery)37
affected, err := queries.ReceiveDelivery(ctx, delivery)32
if err != nil {38
if err != nil {33
return fmt.Errorf("receiving %s: %w", delivery.Item, err)39
return fmt.Errorf("receiving %s: %w", delivery.Item, err)34
}40
}35
fmt.Fprintf(output, "%-8s delivery %d: +%d, now %d in stock\n",41
row, err := queries.GetStock(ctx, delivery.Item)36
row.Item, row.Deliveries, delivery.Quantity, row.Quantity)42
if err != nil {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)37
}51
}38
52
39
// AddItem uses DO NOTHING, and execrows reports whether the row went in: 1 for a new53
// AddItem sets item = item on a duplicate, which changes nothing, so MySQL counts 040
// item, 0 when the item was already there and the insert was skipped.54
// rows: execrows reports 1 for a new item and 0 when the item was already there. It is55
// MySQL's form of ON CONFLICT DO NOTHING; INSERT IGNORE would also hide errors such as a56
// value too long for its column.41
for _, item := range []string{"peas", "cod"} {57
for _, item := range []string{"peas", "cod"} {42
added, err := queries.AddItem(ctx, item)58
added, err := queries.AddItem(ctx, item)43
if err != nil {59
if err != nil {44
return fmt.Errorf("adding %s: %w", item, err)60
return fmt.Errorf("adding %s: %w", item, err)45
}61
}46
if added == 0 {62
if added == 0 {47
fmt.Fprintf(output, "%s is already stocked, nothing changed\n", item)63
fmt.Fprintf(output, "%s is already stocked, nothing changed\n", item)48
continue64
continue49
}65
}50
fmt.Fprintf(output, "added %s with no stock yet\n", item)66
fmt.Fprintf(output, "added %s with no stock yet\n", item)51
}67
}52
68
53
stock, err := queries.ListStock(ctx)69
stock, err := queries.ListStock(ctx)54
if err != nil {70
if err != nil {55
return fmt.Errorf("listing stock: %w", err)71
return fmt.Errorf("listing stock: %w", err)56
}72
}57
for _, row := range stock {73
for _, row := range stock {58
fmt.Fprintf(output, "%-8s %2d\n", row.Item, row.Quantity)74
fmt.Fprintf(output, "%-8s %2d\n", row.Item, row.Quantity)59
}75
}60
return nil76
return nil61
}77
}Go type differences
The same SQL types map to different Go types, because each database reports them differently.
| Query | Field | CockroachDB | MariaDB |
|---|---|---|---|
| ReceiveDelivery | parameter quantity | int64 | int32 |
| ListStock | column quantity | int64 | int32 |
| ListStock | column deliveries | int64 | int32 |