private Expression BuildIndexExpression(SqlTableExpression table, string indexName, Tuple <IndexAttribute, PropertyDescriptor>[] properties)
{
Expression where = null;
var unique = properties.Select(c => c.Item1).Any(c => c.Unique);
var lowercaseIndex = properties.Any(c => c.Item1.LowercaseIndex);
var indexType = properties.Select(c => c.Item1.IndexType).FirstOrDefault(c => c != IndexType.Default);
var sorted = properties.OrderBy(c => c.Item1.CompositeOrder, Comparer <int> .Default);
var indexedColumns = new List <SqlIndexedColumnExpression>();
foreach (var attributeAndProperty in sorted.Where(c => !c.Item1.IncludeOnly))
{
foreach (var columnInfo in QueryBinder.GetColumnInfos(this.model.TypeDescriptorProvider, attributeAndProperty.Item2))
{
indexedColumns.Add(new SqlIndexedColumnExpression(new SqlColumnExpression(columnInfo.DefinitionProperty.PropertyType, null, columnInfo.ColumnName), attributeAndProperty.Item1.SortOrder, attributeAndProperty.Item1.LowercaseIndex));
}
}
var includedColumns = new List <SqlIndexedColumnExpression>();
foreach (var attributeAndProperty in sorted.Where(c => c.Item1.IncludeOnly))
{
foreach (var columnInfo in QueryBinder.GetColumnInfos(this.model.TypeDescriptorProvider, attributeAndProperty.Item2))
{
includedColumns.Add(new SqlIndexedColumnExpression(new SqlColumnExpression(columnInfo.DefinitionProperty.PropertyType, null, columnInfo.ColumnName)));
}
}
Debug.Assert(properties.Select(c => c.Item2.PropertyInfo.DeclaringType).Distinct().Count() == 1);
var parameterExpression = Expression.Parameter(properties.First().Item2.PropertyInfo.DeclaringType);
foreach (var attributeAndProperty in sorted.Where(c => !c.Item1.Condition.IsNullOrEmpty()))
{
var expression = ComputedExpressionParser.Parse(attributeAndProperty.Item1.Condition, attributeAndProperty.Item2, parameterExpression, null, typeof(bool));
if (expression == null)
{
continue;
}
where = where == null ? expression.Body : Expression.And(where, expression.Body);
}
if (where != null)
{
where = Expression.Lambda(where, parameterExpression);
var call = Expression.Call(null, MethodInfoFastRef.QueryableWhereMethod.MakeGenericMethod(parameterExpression.Type), Expression.Constant(null, typeof(DataAccessObjects <>).MakeGenericType(parameterExpression.Type)), where);
var projection = (SqlProjectionExpression)SqlQueryProvider.Optimize(this.dataAccessModel, SqlQueryProvider.Bind(this.dataAccessModel, this.sqlDataTypeProvider, call));
where = projection.Select.Where;
where = AliasReferenceReplacer.Replace(where, ((SqlTableExpression)projection.Select.From).Alias, null);
}
return(new SqlCreateIndexExpression(indexName, table, unique, lowercaseIndex, indexType, false, indexedColumns, includedColumns, where));
}
protected override Expression VisitSelect(SqlSelectExpression selectExpression)
{
if (selectExpression.Skip != null)
{
var rowNumber = new SqlFunctionCallExpression(typeof(int), "ROW_NUMBER");
var oldAliases = (selectExpression.From as ISqlExposesAliases)?.Aliases;
var innerSelectWithRowAlias = selectExpression.Alias + "_ROW";
var cols = selectExpression.Columns.Select(c => new SqlColumnDeclaration(c.Name, new SqlColumnExpression(c.Expression.Type, selectExpression.Alias, c.Name))).ToList();
var over = new SqlOverExpression(rowNumber, selectExpression.OrderBy?.Cast <SqlOrderByExpression>().ToReadOnlyCollection() ?? cols.Select(c => new SqlOrderByExpression(OrderType.Ascending, c.Expression)).ToReadOnlyCollection());
if (oldAliases != null)
{
over = (SqlOverExpression)AliasReferenceReplacer.Replace(over, oldAliases.Contains, selectExpression.Alias);
}
var rowColumn = new SqlColumnDeclaration(RowColumnName, over);
cols.Add(rowColumn);
var innerSelectWithRowColumns = cols.ToReadOnlyCollection();
var innerSelectWithRow = new SqlSelectExpression(selectExpression.Type, innerSelectWithRowAlias, innerSelectWithRowColumns, selectExpression.ChangeOrderBy(null).ChangeSkipTake(null, null), null, null, null, false, null, null, false);
var outerColumns = selectExpression.Columns.Select(c => new SqlColumnDeclaration(c.Name, new SqlColumnExpression(c.Expression.Type, innerSelectWithRowAlias, c.Name)));
Expression rowPredicate = Expression.GreaterThan(new SqlColumnExpression(typeof(int), innerSelectWithRowAlias, rowColumn.Name), selectExpression.Skip);
if (selectExpression.Take != null && !(selectExpression.Take is SqlTakeAllValueExpression))
{
rowPredicate = Expression.And
(
rowPredicate,
Expression.LessThanOrEqual(new SqlColumnExpression(typeof(int), innerSelectWithRowAlias, rowColumn.Name), Expression.Add(selectExpression.Skip, selectExpression.Take))
);
}
var newOrderBy = selectExpression
.OrderBy?
.Select(c => oldAliases == null ? c : AliasReferenceReplacer.Replace(c, oldAliases.Contains, innerSelectWithRowAlias))
.Concat(new SqlOrderByExpression(OrderType.Ascending, new SqlColumnExpression(typeof(int), innerSelectWithRowAlias, rowColumn.Name)))
.ToReadOnlyCollection();
var retval = new SqlSelectExpression(selectExpression.Type, selectExpression.Alias, outerColumns, innerSelectWithRow, rowPredicate, newOrderBy, selectExpression.ForUpdate);
return(retval);
}
return(base.VisitSelect(selectExpression));
}
