MCP Tools Reference: spanner.googleapis.com

Tool: update_database_schema

Update schema for a given database.

The following sample demonstrate how to use curl to invoke the update_database_schema MCP tool.

Curl Request 
                  
curl --location 'https://spanner.googleapis.com/mcp' \
--header 'content-type: application/json' \
--header 'accept: application/json, text/event-stream' \
--data '{
  "method": "tools/call",
  "params": {
    "name": "update_database_schema",
    "arguments": {
      // provide these details according to the tool's MCP specification
    }
  },
  "jsonrpc": "2.0",
  "id": 1
}'

Input Schema

Enqueues the given DDL statements to be applied, in order but not necessarily all at once, to the database schema at some point (or points) in the future. The server checks that the statements are executable (syntactically valid, name tables that exist, etc.) before enqueueing them, but they may still fail upon later execution (for example, if a statement from another batch of statements is applied first and it conflicts in some way, or if there is some data-related problem like a NULL value in a column to which NOT NULL would be added). If a statement fails, all subsequent statements in the batch are automatically cancelled.

Each batch of statements is assigned a name which can be used with the Operations API to monitor progress. See the operation_id field for more details.

UpdateDatabaseDdlRequest

JSON representation 
{
  "database": string,
  "statements": [
    string
  ],
  "operationId": string,
  "protoDescriptors": string
}
Fields
database

string

Required. The database to update.
statements[]

string

Required. DDL statements to be applied to the database.
operationId

string

If empty, the new update request is assigned an automatically-generated operation ID. Otherwise, operation_id is used to construct the name of the resulting Operation.

Specifying an explicit operation ID simplifies determining whether the statements were executed in the event that the UpdateDatabaseDdl call is replayed, or the return value is otherwise lost: the database and operation_id fields can be combined to form the name of the resulting longrunning.Operation: <database>/operations/<operation_id>.

operation_id should be unique within the database, and must be a valid identifier: [a-z][a-z0-9_]*. Note that automatically-generated operation IDs always begin with an underscore. If the named operation already exists, UpdateDatabaseDdl returns ALREADY_EXISTS.
protoDescriptors

string (bytes format)

Optional. Proto descriptors used by CREATE/ALTER PROTO BUNDLE statements. Contains a protobuf-serialized google.protobuf.FileDescriptorSet. To generate it, install and run protoc with --include_imports and --descriptor_set_out. For example, to generate for moon/shot/app.proto, run

$protoc  --proto_path=/app_path --proto_path=/lib_path \
         --include_imports \
         --descriptor_set_out=descriptors.data \
         moon/shot/app.proto

For more details, see protobuffer self description.

A base64-encoded string.

Output Schema

This resource represents a long-running operation that is the result of a network API call.

Operation

JSON representation 
{
  "name": string,
  "metadata": {
    "@type": string,
    field1: ...,
    ...
  },
  "done": boolean,

  // Union field result can be only one of the following:
  "error": {
    object (Status)
  },
  "response": {
    "@type": string,
    field1: ...,
    ...
  }
  // End of list of possible types for union field result.
}
Fields
name

string

The server-assigned name, which is only unique within the same service that originally returns it. If you use the default HTTP mapping, the name should be a resource name ending with operations/{unique_id}.
metadata

object

Service-specific metadata associated with the operation. It typically contains progress information and common metadata such as create time. Some services might not provide such metadata. Any method that returns a long-running operation should document the metadata type, if any.

An object containing fields of an arbitrary type. An additional field "@type" contains a URI identifying the type. Example: { "id": 1234, "@type": "types.example.com/standard/id" }.
done

boolean

If the value is false, it means the operation is still in progress. If true, the operation is completed, and either error or response is available.
Union field result. The operation result, which can be either an error or a valid response. If done == false, neither error nor response is set. If done == true, exactly one of error or response can be set. Some services might not provide the result. result can be only one of the following:
error

object (Status)

The error result of the operation in case of failure or cancellation.
response

object

The normal, successful response of the operation. If the original method returns no data on success, such as Delete, the response is google.protobuf.Empty. If the original method is standard Get/Create/Update, the response should be the resource. For other methods, the response should have the type XxxResponse, where Xxx is the original method name. For example, if the original method name is TakeSnapshot(), the inferred response type is TakeSnapshotResponse.

An object containing fields of an arbitrary type. An additional field "@type" contains a URI identifying the type. Example: { "id": 1234, "@type": "types.example.com/standard/id" }.

Any

JSON representation 
{
  "typeUrl": string,
  "value": string
}
Fields
typeUrl

string

Identifies the type of the serialized Protobuf message with a URI reference consisting of a prefix ending in a slash and the fully-qualified type name.

Example: type.googleapis.com/google.protobuf.StringValue

This string must contain at least one / character, and the content after the last / must be the fully-qualified name of the type in canonical form, without a leading dot. Do not write a scheme on these URI references so that clients do not attempt to contact them.

The prefix is arbitrary and Protobuf implementations are expected to simply strip off everything up to and including the last / to identify the type. type.googleapis.com/ is a common default prefix that some legacy implementations require. This prefix does not indicate the origin of the type, and URIs containing it are not expected to respond to any requests.

All type URL strings must be legal URI references with the additional restriction (for the text format) that the content of the reference must consist only of alphanumeric characters, percent-encoded escapes, and characters in the following set (not including the outer backticks): /-.~_!$&()*+,;=. Despite our allowing percent encodings, implementations should not unescape them to prevent confusion with existing parsers. For example, type.googleapis.com%2FFoo should be rejected.

In the original design of Any, the possibility of launching a type resolution service at these type URLs was considered but Protobuf never implemented one and considers contacting these URLs to be problematic and a potential security issue. Do not attempt to contact type URLs.
value

string (bytes format)

Holds a Protobuf serialization of the type described by type_url.

A base64-encoded string.

Status

JSON representation 
{
  "code": integer,
  "message": string,
  "details": [
    {
      "@type": string,
      field1: ...,
      ...
    }
  ]
}
Fields
code

integer

The status code, which should be an enum value of google.rpc.Code.
message

string

A developer-facing error message, which should be in English. Any user-facing error message should be localized and sent in the google.rpc.Status.details field, or localized by the client.
details[]

object

A list of messages that carry the error details. There is a common set of message types for APIs to use.

An object containing fields of an arbitrary type. An additional field "@type" contains a URI identifying the type. Example: { "id": 1234, "@type": "types.example.com/standard/id" }.

Tool Annotations

Destructive Hint: ✅ | Idempotent Hint: ❌ | Read Only Hint: ❌ | Open World Hint: ❌