Database.UnsafeInsert.md in framework/master/Signum/Engine

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Database.UnsafeInsert

UnsafeInsert extension method let you create efficient low-level INSERT statements without creating the entities and inserting them one by one.

The method is call Unsafe for reason: Validation won't take place in this low-level method.

Still, you'll have a compile-time checked LINQ experience, with security and query filtering also taking place.

public static int UnsafeInsert<T, E>(this IQueryable<T> query, Expression<Func<T, E>> constructor)
    where E : Entity

UnsafeInsert takes an arbitrary IQueryable<T> and for each result creates a new entity using the constructor expression.

Example:

int inserted = Database.Query<ProjectEntity>()
              .UnsafeInsert(p => new BugEntity
              {
                   Description = "Initial bug of " + p.Name,
                   Start = DateTime.Now,
                   End = null,
                   Fixer = null,
                   Discoverer =  null,
                   Status = Status.Open,
                   Project = p.ToLite(),
                   Ticks = 0,
              });

Will be translated to:

INSERT INTO BugEntity(Description, Start, [End], idFixer, 
idDiscoverer_Customer, idDiscoverer_Developer, idStatus, idProject, 
Ticks)
SELECT ('Initial bug of ' + ISNULL(s0.Name, '')), convert(datetime, '2014-08-26T11:38:19', 126), NULL, NULL, 
NULL, NULL, 0, s0.Id, 
0 FROM (
  (SELECT pdn.Name, pdn.Id
  FROM ProjectEntity AS pdn)
) AS s0;

SELECT @@rowcount

This API requires you to set every single required field, because the initial values set in the field initializers are not accessible to the LINQ provider. The constructor should be a new expression, but can also contain calls to SetReadOnly and SetMixin. For example:

int inserted = Database.Query<ProjectEntity>()
             .UnsafeInsert(p => new BugEntity
             {
                 Description = "Initial bug of " + p.Name,
                 Start = DateTime.Now,
                 End = null,
                 Fixer = null,
                 Discoverer = null,
                 Status = Status.Open,
                 Project = p.ToLite(),
                 Ticks = 0,
             }.SetReadonly(b => b.CreationTime, b => DateTime.Now)
             .SetMixin((CorruptMixin c) => c.Corrupt, b => true));

Before deleting the entities, PreUnsafeInsert will be called in EntityEvents.

Database.UnsafeInsertMList

Allows you to send low-level INSERT statements to MListTables.

public static int UnsafeInsertMList<T, E, V>(this IQueryable<T> query, 
	Expression<Func<E, MList<V>>> mListProperty,  
	Expression<Func<T, MListElement<E, V>>> constructor)
    where E : Entity)

The method takes a expression to mListProperty to unambiguously determine the MListTable, and a constructor that has to create the MListElement<E, V>.

Example:

INSERT INTO BugDNComments(idParent, HasValue, Text, Date, 
idWriter_Customer, idWriter_Developer)
SELECT s2.Id, 1, (ISNULL((ISNULL(('Coment of ' + ISNULL(s2.Name, '')), '') + ' in '), '') + ISNULL(s2.Description, '')), convert(datetime, '2014-08-26T13:07:50', 126), 
NULL, s2.Id1 FROM (
  (SELECT bdn.Id, ddn.Name, bdn.Description, ddn.Id AS Id1
  FROM DeveloperEntity AS ddn
  CROSS JOIN BugEntity AS bdn)
) AS s2;
SELECT @@rowcount

Signum Documentation

Database.UnsafeInsert

Database.UnsafeInsertMList

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