protected override IEnumerable <MigrationOperation> Diff(TableMapping source,
TableMapping target, DiffContext diffContext)
{
if (source.Schema != target.Schema ||
source.Name != target.Name)
{
// 如果是创建分表操作
var entityType = target.EntityTypes[0];
if (entityType.ClrType.IsDefined <ShardableAttribute>())
{
// 不使用 Add 方法创建表操作，会添加重复的索引导致异常
var createTableOperation = new CreateTableOperation
{
Schema = target.Schema,
Name = target.Name,
Comment = target.GetComment()
};
createTableOperation.AddAnnotations(MigrationsAnnotations.For(entityType));
createTableOperation.Columns.AddRange
(GetSortedProperties(target)
.SelectMany(p => Add(p, diffContext, inline: true))
.Cast <AddColumnOperation>());
var primaryKey = entityType.FindPrimaryKey();
if (primaryKey != null)
{
createTableOperation.PrimaryKey = Add(primaryKey, diffContext).Cast <AddPrimaryKeyOperation>().Single();
}
createTableOperation.UniqueConstraints.AddRange(
target.GetKeys().Where(k => !k.IsPrimaryKey()).SelectMany(k => Add(k, diffContext))
.Cast <AddUniqueConstraintOperation>());
createTableOperation.CheckConstraints.AddRange(
target.GetCheckConstraints().SelectMany(c => Add(c, diffContext))
.Cast <CreateCheckConstraintOperation>());
foreach (var targetEntityType in target.EntityTypes)
{
diffContext.AddCreate(targetEntityType, createTableOperation);
}
yield return(createTableOperation);
yield break; // 跳出迭代，防止出现重复的添加主键、索引等相关操作
}
else
{
yield return(new RenameTableOperation
{
Schema = source.Schema,
Name = source.Name,
NewSchema = target.Schema,
NewName = target.Name
});
}
}
// Validation should ensure that all the relevant annotations for the collocated entity types are the same
var sourceMigrationsAnnotations = MigrationsAnnotations.For(source.EntityTypes[0]).ToList();
var targetMigrationsAnnotations = MigrationsAnnotations.For(target.EntityTypes[0]).ToList();
if (source.GetComment() != target.GetComment() ||
HasDifferences(sourceMigrationsAnnotations, targetMigrationsAnnotations))
{
var alterTableOperation = new AlterTableOperation
{
Name = target.Name,
Schema = target.Schema,
Comment = target.GetComment(),
OldTable = { Comment = source.GetComment() }
};
alterTableOperation.AddAnnotations(targetMigrationsAnnotations);
alterTableOperation.OldTable.AddAnnotations(sourceMigrationsAnnotations);
yield return(alterTableOperation);
}
var operations = Diff(source.GetProperties(), target.GetProperties(), diffContext)
.Concat(Diff(source.GetKeys(), target.GetKeys(), diffContext))
.Concat(Diff(source.GetIndexes(), target.GetIndexes(), diffContext))
.Concat(Diff(source.GetCheckConstraints(), target.GetCheckConstraints(), diffContext));
foreach (var operation in operations)
{
yield return(operation);
}
DiffData(source, target, diffContext);
}