COPY TO Couchbase Data Service Statements

Capella Columnar

reference

This topic describes how you use COPY TO statements to write the results of a query—or a copy of an entire collection—out to a collection on Capella or Couchbase Server.

For more information and use cases for this operation, see Copy Results to a Couchbase Collection.

Syntax

CopyToCouchbase EBNF

CopyToCouchbase ::= "COPY" SourceDefinition
           "TO" CollectionQualifiedName
           "AT" LinkName
           "KEY" (KeyExpr | "AUTOGENERATED")
           ("WITH" WithClause)?

CopyToCouchbase Diagram

"COPY" SourceDefinition "TO" CollectionQualifiedName "AT" LinkName "KEY" (KeyExpr | "AUTOGENERATED") ("WITH" WithClause)?

Show SourceDefinition Diagram

( QualifiedName | "(" Query ")" ) ("AS"? AliasIdentifier )?

SourceDefinition

Show CollectionQualifiedName Diagram

CollectionQualifiedName

Show KeyExpr Diagram

KeyExpr

Show WithClause Diagram

"WITH" "{" NameValuePair ("," NameValuePair )* "}"

WithClause

Show NameValuePair Diagram

NameValuePair

Examples

This example runs a COPY TO statement on a Capella Columnar collection that shadows operational data. As a prerequisite for running this example yourself, follow the add sample data procedures to add remote collections to Capella Columnar. In a Capella operational database, you also add a target copyToTest bucket with a beer scope and a cali collection.

This example uses the credentials stored in the capellaLink remote link to copy documents in the Capella Columnar remoteCapella.remoteBeer.beerUs collection to the Capella collection.

  COPY (
    SELECT name, city, code, website
    FROM remoteCapella.remoteBeer.beerUs
    WHERE state = "California")
    AS b
  TO copyToTest.beer.cali
  AT capellaLink
  KEY uppercase(b.name) || "-" || to_string(b.code);

In Capella, you can query the target copyToTest.beer.cali collection to verify this operation. See Read Data and Return Results.

Show an additional example

This example runs a COPY TO statement on an external collection in Capella Columnar that supports queries of data in an Amazon S3 bucket. It copies to a target copyMusic bucket in a Capella operational database with a copyMusic scope and an countrySongs collection.

This example uses credentials stored in a capellaLink remote link to copy documents in a music.myPlaylist.countrySongs collection to the Capella collection.

As an external collection, the music.myPlaylist.countrySongs collection provides the destination path to data in an Amazon S3 bucket.

In Capella Columnar:

  COPY music.myPlaylist.countrySongs
    TO copyMusic.myPlaylist.countrySongs
    AT capellaLink
    KEY AUTOGENERATED;

The result is a complete copy of data in the Amazon S3 bucket referenced by music.myPlaylist.countrySongs in a Capella collection in JSON format.

In Capella, you can query the target copyMusic.myPlaylist.countrySongs collection to verify this operation. See Read Data and Return Results.

Arguments

SourceDefinition

As the source, you specify either the fully qualified name of a Capella Columnar collection or a query.

If you specify a Capella Columnar collection name, then the whole collection—or view or synonym—is the source of data to copy.
If you specify a query, then the result of that query is the source of data.

TO: The TO clause identifies the fully qualified name of a collection on Capella or Couchbase Server.
AT: The AT clause specifies the name of the Capella Columnar link that contains credentials for accessing the Capella operational database or Couchbase Server cluster.

KEY

The KEY evaluates to be the key for each document in the Capella or Couchbase Server collection. For the KeyExpr you can provide:

The name of a key (field) found in the source documents.
An expression that evaluates to a string, and that can involve multiple keys and functions.
AUTOGENERATED, which generates a UUID.

See Introduction: Document Keys.

COPY TO Couchbase Data Service Statements

Syntax

Examples

Arguments

See Also