Class HistoryRepository

Namespace

Microsoft.EntityFrameworkCore.Migrations

Assembly

Microsoft.EntityFrameworkCore.Relational.dll

A base class for the repository used to access the '__EFMigrationsHistory' table that tracks metadata about EF Core Migrations such as which migrations have been applied.

Database providers must inherit from this class to implement provider-specific functionality.

The service lifetime is Scoped. This means that each Microsoft.EntityFrameworkCore.DbContext instance will use its own instance of this service. The implementation may depend on other services registered with any lifetime. The implementation does not need to be thread-safe.

public abstract class HistoryRepository : IHistoryRepository

Inheritance

object

HistoryRepository

Implements

IHistoryRepository

Inherited Members

object.GetType()

object.MemberwiseClone()

object.ToString()

object.Equals(object)

object.Equals(object, object)

object.ReferenceEquals(object, object)

object.GetHashCode()

Constructors

HistoryRepository(HistoryRepositoryDependencies)

Initializes a new instance of this class.

protected HistoryRepository(HistoryRepositoryDependencies dependencies)

Parameters

dependencies HistoryRepositoryDependencies

Parameter object containing dependencies for this service.

Fields

DefaultTableName

The default name for the Migrations history table.

public const string DefaultTableName = "__EFMigrationsHistory"

Field Value

string

Properties

Dependencies

Parameter object containing service dependencies.

protected virtual HistoryRepositoryDependencies Dependencies { get; }

Property Value

HistoryRepositoryDependencies

ExistsSql

Overridden by database providers to generate SQL that tests for existence of the history table.

protected abstract string ExistsSql { get; }

Property Value

string

GetAppliedMigrationsSql

Generates SQL to query for the migrations that have been applied.

protected virtual string GetAppliedMigrationsSql { get; }

Property Value

string

MigrationIdColumnName

The name of the column that holds the Migration identifier.

protected virtual string MigrationIdColumnName { get; }

Property Value

string

ProductVersionColumnName

The name of the column that contains the Entity Framework product version.

protected virtual string ProductVersionColumnName { get; }

Property Value

string

SqlGenerationHelper

A helper class for generation of SQL.

protected virtual ISqlGenerationHelper SqlGenerationHelper { get; }

Property Value

ISqlGenerationHelper

TableName

THe history table name.

protected virtual string TableName { get; }

Property Value

string

TableSchema

The schema that contains the history table, or null if the default schema should be used.

protected virtual string TableSchema { get; }

Property Value

string

Methods

ConfigureTable(EntityTypeBuilder<HistoryRow>)

Configures the entity type mapped to the history table.

Database providers can override this to add or replace configuration.

protected virtual void ConfigureTable(EntityTypeBuilder<HistoryRow> history)

Parameters

history EntityTypeBuilder<HistoryRow>

A builder for the HistoryRow entity type.

Exists()

Checks whether or not the history table exists.

public virtual bool Exists()

Returns

bool

true if the table already exists, false otherwise.

ExistsAsync(CancellationToken)

Checks whether or not the history table exists.

public virtual Task<bool> ExistsAsync(CancellationToken cancellationToken = default)

Parameters

cancellationToken CancellationToken

A CancellationToken to observe while waiting for the task to complete.

Returns

Task<bool>

A task that represents the asynchronous operation. The task result contains true if the table already exists, false otherwise.

GetAppliedMigrations()

Queries the history table for all migrations that have been applied.

public virtual IReadOnlyList<HistoryRow> GetAppliedMigrations()

Returns

IReadOnlyList<HistoryRow>

The list of applied migrations, as HistoryRow entities.

GetAppliedMigrationsAsync(CancellationToken)

Queries the history table for all migrations that have been applied.

public virtual Task<IReadOnlyList<HistoryRow>> GetAppliedMigrationsAsync(CancellationToken cancellationToken = default)

Parameters

cancellationToken CancellationToken

A CancellationToken to observe while waiting for the task to complete.

Returns

Task<IReadOnlyList<HistoryRow>>

A task that represents the asynchronous operation. The task result contains the list of applied migrations, as HistoryRow entities.

GetBeginIfExistsScript(string)

Overridden by database providers to generate a SQL Script that will BEGIN a block of SQL if and only if the migration with the given identifier already exists in the history table.

public abstract string GetBeginIfExistsScript(string migrationId)

Parameters

migrationId string

The migration identifier.

Returns

string

The generated SQL.

GetBeginIfNotExistsScript(string)

Overridden by database providers to generate a SQL Script that will BEGIN a block of SQL if and only if the migration with the given identifier does not already exist in the history table.

public abstract string GetBeginIfNotExistsScript(string migrationId)

Parameters

migrationId string

The migration identifier.

Returns

string

The generated SQL.

GetCreateIfNotExistsScript()

Overridden by a database provider to generate a SQL script that will create the history table if and only if it does not already exist.

public abstract string GetCreateIfNotExistsScript()

Returns

string

The SQL script.

GetCreateScript()

Generates a SQL script that will create the history table.

public virtual string GetCreateScript()

Returns

string

The SQL script.

GetDeleteScript(string)

Generates a SQL script to delete a row from the history table.

public virtual string GetDeleteScript(string migrationId)

Parameters

migrationId string

The migration identifier of the row to delete.

Returns

string

The generated SQL.

GetEndIfScript()

Overridden by database providers to generate a SQL script to END the SQL block.

public abstract string GetEndIfScript()

Returns

string

The generated SQL.

GetInsertScript(HistoryRow)

Generates a SQL script to insert a row into the history table.

public virtual string GetInsertScript(HistoryRow row)

Parameters

row HistoryRow

The row to insert, represented as a HistoryRow entity.

Returns

string

The generated SQL.

InterpretExistsResult(object)

Interprets the result of executing ExistsSql.

protected abstract bool InterpretExistsResult(object value)

Parameters

value object

Returns

bool

true if the table already exists, false otherwise.