schema-core (schema-commands)

The schema-commands crate (also known as schema-core) provides the core functionality for the Prisma schema engine, including migrations, introspection, and schema operations.

Overview

This library implements all schema engine commands that are exposed through the JSON-RPC API. It handles database migrations, schema introspection, schema diffing, and validation.

Installation

[dependencies]
schema-commands = "0.1.0"

Core Modules

Commands

The commands module contains implementations for all schema engine operations:

apply_migrations - Apply pending migrations to the database
create_migration - Create a new migration from schema changes
dev_diagnostic - Run development-time diagnostics
diagnose_migration_history - Analyze migration history for issues
diff - Compare two schemas and show differences
evaluate_data_loss - Analyze potential data loss in migrations
introspect_sql - Introspect a database and generate a schema
mark_migration_applied - Mark a migration as applied without running it
mark_migration_rolled_back - Mark a migration as rolled back
schema_push - Push schema changes directly to the database

Key Types

GenericApi

The main API trait for schema engine operations.

pub trait GenericApi {
    async fn apply_migrations(&self, input: ApplyMigrationsInput) -> CoreResult<ApplyMigrationsOutput>;
    async fn create_migration(&self, input: CreateMigrationInput) -> CoreResult<CreateMigrationOutput>;
    async fn dev_diagnostic(&self, input: DevDiagnosticInput) -> CoreResult<DevDiagnosticOutput>;
    async fn diagnose_migration_history(&self, input: DiagnoseMigrationHistoryInput) -> CoreResult<DiagnoseMigrationHistoryOutput>;
    async fn diff(&self, input: DiffInput) -> CoreResult<DiffOutput>;
    async fn evaluate_data_loss(&self, input: EvaluateDataLossInput) -> CoreResult<EvaluateDataLossOutput>;
    async fn introspect(&self, input: IntrospectSqlInput) -> CoreResult<IntrospectSqlOutput>;
    async fn mark_migration_applied(&self, input: MarkMigrationAppliedInput) -> CoreResult<MarkMigrationAppliedOutput>;
    async fn mark_migration_rolled_back(&self, input: MarkMigrationRolledBackInput) -> CoreResult<MarkMigrationRolledBackOutput>;
    async fn schema_push(&self, input: SchemaPushInput) -> CoreResult<SchemaPushOutput>;
}

CoreError

Error type for schema engine operations.

pub enum CoreError {
    SchemaParserError(Diagnostics),
    ConnectorError(ConnectorError),
    Generic(String),
    // ... other variants
}

Diagnostics

Schema parsing and validation errors

ConnectorError

Database connector errors

String

Generic error with message

Schema Operations

Introspection

Introspect a database and generate a Prisma schema.

pub async fn introspect(
    schema: SchemaContainer,
    connection_string: String,
) -> CoreResult<IntrospectSqlOutput>

SchemaContainer

Base schema with datasource configuration

String

Database connection string to introspect

object

Contains the generated schema and warnings

schema - Generated Prisma schema
warnings - Introspection warnings
views - Database views discovered

Create Migration

Create a new migration from schema changes.

pub async fn create_migration(
    input: CreateMigrationInput,
) -> CoreResult<CreateMigrationOutput>

String

Name for the new migration

SchemaContainer

The target schema to migrate to

bool

Whether to create a draft migration

object

migration_id - ID of the created migration
migration_script - SQL script for the migration
warnings - Warnings about the migration

Apply Migrations

Apply pending migrations to the database.

pub async fn apply_migrations(
    input: ApplyMigrationsInput,
) -> CoreResult<ApplyMigrationsOutput>

String

Path to the migrations directory

SchemaContainer

The Prisma schema

object

applied_migration_names - List of applied migration names
warnings - Warnings from applying migrations

Schema Push

Push schema changes directly to the database without migrations.

pub async fn schema_push(
    input: SchemaPushInput,
) -> CoreResult<SchemaPushOutput>

SchemaContainer

The schema to push

bool

Whether to force push even with data loss

object

executed_steps - Number of steps executed
warnings - Push warnings
unexecutable - Reasons why push failed (if applicable)

Diff

Compare two schemas or a schema and database.

pub async fn diff(
    input: DiffInput,
) -> CoreResult<DiffOutput>

DiffTarget

Source schema or database

DiffTarget

Target schema or database

bool

Whether to return SQL script or human-readable diff

object

diff - The diff as SQL script or human-readable format
exit_code - Exit code (0 if no changes, 2 if changes)

Helper Functions

dialect_for_provider

Create a schema dialect for a given provider.

pub fn dialect_for_provider(provider: &str) -> CoreResult<Box<dyn SchemaDialect>>

&str

required

Database provider name (postgresql, mysql, sqlite, mssql, mongodb)

Box<dyn SchemaDialect>

The schema dialect implementation for the provider

extract_namespaces

Extract database namespaces from schema files.

pub fn extract_namespaces(
    files: &[(String, SourceFile)],
    namespaces: &mut Vec<String>,
    preview_features: &mut BitFlags<PreviewFeature>,
)

Feature Flags

Database provider support is controlled by feature flags:

[features]
postgresql = ["sql-schema-connector/postgresql"]
postgresql-native = ["postgresql"]
sqlite = ["sql-schema-connector/sqlite"]
sqlite-native = ["sqlite"]
mysql = ["sql-schema-connector/mysql"]
mysql-native = ["mysql"]
mssql = ["sql-schema-connector/mssql"]
mssql-native = ["mssql"]
cockroachdb = ["sql-schema-connector/cockroachdb"]
cockroachdb-native = ["cockroachdb"]
mongodb = ["mongodb-schema-connector"]
mongodb-native = ["mongodb"]
all-native = [
    "postgresql-native",
    "sqlite-native",
    "mysql-native",
    "mssql-native",
    "cockroachdb-native",
    "mongodb-native",
]

Dependencies

Key dependencies:

psl - Prisma Schema Language parser
schema-connector - Schema connector trait
sql-schema-connector - SQL database schema operations
mongodb-schema-connector - MongoDB schema operations (optional)
quaint - Database abstraction layer
user-facing-errors - User-friendly error messages
jsonrpc-core - JSON-RPC protocol support

Examples

Introspecting a Database

use schema_commands::{GenericApi, IntrospectSqlInput};

let input = IntrospectSqlInput {
    schema: SchemaContainer {
        path: "schema.prisma".to_string(),
        content: "datasource db { provider = \"postgresql\" }".to_string(),
    },
    connection_string: "postgresql://localhost/mydb".to_string(),
    composite_type_depth: -1,
};

let output = api.introspect(input).await?;
println!("Generated schema:\n{}", output.schema);

Creating a Migration

use schema_commands::{GenericApi, CreateMigrationInput};

let input = CreateMigrationInput {
    migrations_directory_path: "./prisma/migrations".to_string(),
    schema: schema_container,
    migration_name: "add_user_table".to_string(),
    draft: false,
};

let output = api.create_migration(input).await?;
println!("Created migration: {}", output.migration_id);
println!("SQL:\n{}", output.migration_script);

Pushing Schema Changes

use schema_commands::{GenericApi, SchemaPushInput};

let input = SchemaPushInput {
    schema: schema_container,
    force: false,
};

let output = api.schema_push(input).await?;
if output.executed_steps > 0 {
    println!("Applied {} changes", output.executed_steps);
}

psl-core - Schema parsing and validation
Schema Engine Overview - Architecture guide
Migrations Guide - Migration workflows

Libraries

Binaries

Connectors

schema-core (schema-commands)

Overview

Installation

Core Modules

Commands

Key Types

GenericApi

CoreError

Schema Operations

Introspection

Create Migration

Apply Migrations

Schema Push

Diff

Helper Functions

dialect_for_provider

extract_namespaces

Feature Flags

Dependencies

Examples

Introspecting a Database

Creating a Migration

Pushing Schema Changes

​Overview

​Installation

​Core Modules

​Commands

​Key Types

​GenericApi

​CoreError

​Schema Operations

​Introspection

​Create Migration

​Apply Migrations

​Schema Push

​Diff

​Helper Functions

​dialect_for_provider

​extract_namespaces

​Feature Flags

​Dependencies

​Examples

​Introspecting a Database

​Creating a Migration

​Pushing Schema Changes

​Related

Overview

Installation

Core Modules

Commands

Key Types

GenericApi

CoreError

Schema Operations

Introspection

Create Migration

Apply Migrations

Schema Push

Diff

Helper Functions

dialect_for_provider

extract_namespaces

Feature Flags

Dependencies

Examples

Introspecting a Database

Creating a Migration

Pushing Schema Changes

Related