Update operators for tables (Go)

Some Data API commands, like Update a row (Go), use update operators to modify rows in a table.

Set

The $set operator sets the value of the specified column to the specified value.

package main

import (
	"context"
	"log"

	"github.com/datastax/astra-db-go/v2/astra"
	"github.com/datastax/astra-db-go/v2/astra/filter"
	"github.com/datastax/astra-db-go/v2/astra/options"
	"github.com/datastax/astra-db-go/v2/astra/update"
)

func main() {
	ctx := context.Background()
	// Get an existing table
	client := astra.NewClient(
		options.API().SetEnvironment(options.EnvironmentHCD),
	)

	database := client.Database(
		"API_ENDPOINT",
		options.API().
			SetUsernamePasswordTokenProvider(
				"USERNAME",
				"PASSWORD",
			).
			SetKeyspace("KEYSPACE_NAME"),
	)

	table := database.Table("TABLE_NAME")

	// Update a row
	err := table.UpdateOne(
		ctx,
		filter.And(
			filter.Eq("title", "Hidden Shadows of the Past"),
			filter.Eq("author", "John Anthony"),
		),
		update.Table().
			Set("rating", 4.5).
			Set("genres", []string{"Fiction", "Drama"}),
	)
	if err != nil {
		log.Fatal(err)
	}
}

Unset

The $unset operator sets the specified column’s value to null or the equivalent empty form, such as [] or {} for map, list, and set types.

Unsetting a column produces a tombstone. Excessive tombstones can impact query performance.

package main

import (
	"context"
	"log"

	"github.com/datastax/astra-db-go/v2/astra"
	"github.com/datastax/astra-db-go/v2/astra/filter"
	"github.com/datastax/astra-db-go/v2/astra/options"
	"github.com/datastax/astra-db-go/v2/astra/update"
)

func main() {
	ctx := context.Background()
	// Get an existing table
	client := astra.NewClient(
		options.API().SetEnvironment(options.EnvironmentHCD),
	)

	database := client.Database(
		"API_ENDPOINT",
		options.API().
			SetUsernamePasswordTokenProvider(
				"USERNAME",
				"PASSWORD",
			).
			SetKeyspace("KEYSPACE_NAME"),
	)

	table := database.Table("TABLE_NAME")

	// Update a row
	err := table.UpdateOne(
		ctx,
		filter.And(
			filter.Eq("title", "Hidden Shadows of the Past"),
			filter.Eq("author", "John Anthony"),
		),
		update.Table().Unset("genres"),
	)
	if err != nil {
		log.Fatal(err)
	}
}

Combine operators

You can use multiple update operators in a single update.

package main

import (
	"context"
	"log"

	"github.com/datastax/astra-db-go/v2/astra"
	"github.com/datastax/astra-db-go/v2/astra/filter"
	"github.com/datastax/astra-db-go/v2/astra/options"
	"github.com/datastax/astra-db-go/v2/astra/update"
)

func main() {
	ctx := context.Background()
	// Get an existing table
	client := astra.NewClient(
		options.API().SetEnvironment(options.EnvironmentHCD),
	)

	database := client.Database(
		"API_ENDPOINT",
		options.API().
			SetUsernamePasswordTokenProvider(
				"USERNAME",
				"PASSWORD",
			).
			SetKeyspace("KEYSPACE_NAME"),
	)

	table := database.Table("TABLE_NAME")

	// Update a row
	err := table.UpdateOne(
		ctx,
		filter.And(
			filter.Eq("title", "Hidden Shadows of the Past"),
			filter.Eq("author", "John Anthony"),
		),
		update.Table().
			Set("rating", 4.5).
			Set("genres", []string{"Fiction", "Drama"}).
			Unset("borrower"),
	)
	if err != nil {
		log.Fatal(err)
	}
}

Unsupported operators

$rename isn’t supported. Instead, use alterTable to add and drop columns.
$currentDate isn’t supported.
The array operators $push, $each, $pullAll, $addToSet, $pop, and $position aren’t supported.

Update operators for tables (Go)

Set

Unset

Combine operators

Unsupported operators

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