/// <summary>
/// Initializes a new instance of <see cref="DbJoinClause"/> class.
/// </summary>
/// <param name="kind">The operation of SQL JOIN.</param>
/// <param name="left">The left operand.</param>
/// <param name="right">The right operand.</param>
/// <param name="on">The SQL JOIN column mappings.</param>
public DbJoinClause(DbJoinKind kind, DbFromClause left, DbFromClause right, IReadOnlyList <ColumnMapping> on)
{
Kind = kind;
Left = left;
Right = right;
On = on;
}
private IEntity Join(IEntity _, DbJoinKind kind, IReadOnlyList <ColumnMapping> relationship)
{
Debug.Assert(relationship[0].Target.ParentModel == _.Model);
var result = MakeAlias(_);
var resultFromClause = result.Model.FromClause;
if (result != _)
{
resultFromClause = resultFromClause.Clone(result.Model);
relationship = relationship.Select(x => new ColumnMapping(x.SourceExpression, result.Model.Columns[x.Target.Ordinal])).ToList();
}
AddSourceModel(result.Model);
FromClause = new DbJoinClause(kind, FromClause, resultFromClause, EliminateSubQuery(relationship));
return(result);
}
private void Join <T, TKey>(DbSet <T> dbSet, TKey left, TKey right, DbJoinKind kind, out T _)
where T : class, IEntity, new()
where TKey : CandidateKey
{
dbSet.VerifyNotNull(nameof(dbSet));
left.VerifyNotNull(nameof(left));
if (!_sourceModels.Contains(left.ParentModel))
{
throw new ArgumentException(DiagnosticMessages.DbQueryBuilder_Join_InvalidLeftKey, nameof(left));
}
right.VerifyNotNull(nameof(right));
if (right.ParentModel != dbSet.Model)
{
throw new ArgumentException(DiagnosticMessages.DbQueryBuilder_Join_InvalidRightKey, nameof(right));
}
Join(dbSet, kind, left.UnsafeJoin(right), out _);
}
internal static string ToSql(this DbJoinKind kind)
{
if (kind == DbJoinKind.InnerJoin)
{
return("INNER JOIN");
}
else if (kind == DbJoinKind.LeftJoin)
{
return("LEFT JOIN");
}
else if (kind == DbJoinKind.CrossJoin)
{
return("CROSS JOIN");
}
else
{
Debug.Assert(kind == DbJoinKind.RightJoin);
return("RIGHT JOIN");
}
}
private void Join <T>(DbSet <T> dbSet, DbJoinKind kind, IReadOnlyList <ColumnMapping> relationship, out T _)
where T : class, IEntity, new()
{
_ = (T)Join(dbSet._, kind, relationship);
}
