/// <summary>
/// Executes the expression.
/// </summary>
/// <typeparam name="T">The entity type.</typeparam>
/// <param name="expression">The expression.</param>
/// <returns>Returns the result object.</returns>
public T Execute <T>(Expression expression)
{
var genericType = typeof(T);
var isEnumerable = typeof(IEnumerable).IsAssignableFrom(genericType);
var entityType = isEnumerable ? genericType.GenericTypeArguments[0] : genericType;
var methodCallExpression = expression as MethodCallExpression;
if (methodCallExpression != null && methodCallExpression.Method.Name == "Count")
{
entityType = methodCallExpression.Arguments[0].Type.GenericTypeArguments[0];
}
var queryExpressionVisitor = new QueryExpressionVisitor(entityType);
queryExpressionVisitor.RootTableAlias = Settings.RootTableAlias;
queryExpressionVisitor.ParameterAlias = Settings.ParameterAlias;
queryExpressionVisitor.ParameterAliasIndex = Settings.ParameterAliasStartIndex;
queryExpressionVisitor.JoinTableAlias = Settings.JoinTableAlias;
queryExpressionVisitor.JoinTableAliasIndex = Settings.JoinTableAliasStartIndex;
string command;
IQuery query;
if (methodCallExpression != null && methodCallExpression.Method.Name == "Count")
{
command = queryExpressionVisitor.ParseCountQueryExpression(expression);
query = CreateQuery(command, entityType, queryExpressionVisitor);
return(_session.ExecuteScalar <T>(query));
}
command = queryExpressionVisitor.ParseQueryExpression(expression);
query = CreateQuery(command, entityType, queryExpressionVisitor);
var entities = _session.ExecuteQuery(query);
foreach (var include in queryExpressionVisitor.Includes)
{
var propertyInfo = entityType.GetProperty(include);
foreach (var entity in entities)
{
propertyInfo.GetValue(entity);
}
}
if (isEnumerable)
{
var resultList = (IList)Activator.CreateInstance(typeof(List <>).MakeGenericType(entityType));
foreach (var entity in entities)
{
resultList.Add(entity);
}
return((T)resultList);
}
if (methodCallExpression != null)
{
if (methodCallExpression.Method.Name == "First" && entities.Count == 0)
{
throw new InvalidOperationException("The source sequence is empty");
}
if (methodCallExpression.Method.Name == "Single" && (entities.Count == 0 || entities.Count > 1))
{
throw new InvalidOperationException(entities.Count == 0 ? "The source sequence is empty" : "The source sequence contains more than one item");
}
if (methodCallExpression.Method.Name == "SingleOrDefault" && entities.Count > 1)
{
throw new InvalidOperationException("The source sequence contains more than one item");
}
}
return(entities.OfType <T>().FirstOrDefault());
}
protected override Expression VisitMethodCall(MethodCallExpression node)
{
if (node.Method.Name == "Where" || node.Method.Name == "FirstOrDefault" || node.Method.Name == "First" || node.Method.Name == "Single" || node.Method.Name == "SingleOrDefault")
{
if (node.Method.Name == "FirstOrDefault" || node.Method.Name == "First")
{
Limit = 1;
}
Visit(node.Arguments[0]);
if (node.Arguments.Count < 2)
{
return(node);
}
if (!_hasWhere)
{
_hasWhere = true;
EmitSql("WHERE ");
}
else
{
EmitSql(" AND ");
_currentEntityMetadata = _sourceEntityMetadata;
}
Visit(node.Arguments[1]);
return(node);
}
if (node.Method.Name == "Any" || node.Method.Name == "All" || node.Method.Name == "Count")
{
if (!(node.Arguments[0] is MemberExpression))
{
Visit(node.Arguments[0]);
if (node.Arguments.Count == 1)
{
return(node);
}
if (!_hasWhere)
{
_hasWhere = true;
EmitSql("WHERE ");
}
else
{
EmitSql(" AND ");
}
Visit(node.Arguments[1]);
return(node);
}
var fieldMetadata = (FieldBaseMetadata)_currentEntityMetadata.Fields.FirstOrDefault(x => x.Name == (node.Arguments[0] as MemberExpression).Member.Name) ??
_currentEntityMetadata.ListFields.FirstOrDefault(x => x.Name == (node.Arguments[0] as MemberExpression).Member.Name);
string command = null;
IList <TableJoin> joins = null;
if (node.Arguments.Count == 2)
{
_subQueryIndex++;
var qev = new QueryExpressionVisitor(EntityMetadataResolver.EntityMetadata.FirstOrDefault(x => x.Name == fieldMetadata.FieldType))
{
RootTableAlias = $"{RootTableAlias}{_subQueryIndex}",
ParameterAlias = ParameterAlias,
ParameterAliasIndex = ParameterAliasIndex,
JoinTableAlias = JoinTableAlias,
JoinTableAliasIndex = JoinTableAliasIndex
};
qev._currentAlias = qev.RootTableAlias;
//TODO needs beautify
qev.Visit(node.Arguments[1]);
ParameterAliasIndex = qev.ParameterAliasIndex;
foreach (var queryParameter in qev.Parameters)
{
Parameters.Add(queryParameter);
}
command = qev.Command;
joins = qev.Joins;
}
var referenceField = ((ListFieldMetadata)fieldMetadata).ReferenceField;
if (node.Method.Name == "Any")
{
EmitSql(string.IsNullOrWhiteSpace(command)
? $"(SELECT COUNT({RootTableAlias}{_subQueryIndex}.Id) FROM {fieldMetadata.FieldType} {RootTableAlias}{_subQueryIndex} WHERE {RootTableAlias}{_subQueryIndex}.{referenceField} = {_currentAlias}.Id) > 0"
: $"{_currentAlias}.Id IN (SELECT {RootTableAlias}{_subQueryIndex}.{referenceField} FROM {fieldMetadata.FieldType} {RootTableAlias}{_subQueryIndex} {string.Join(Environment.NewLine, joins.Select(x => x.ToString()))} WHERE {command} AND {RootTableAlias}{_subQueryIndex}.{referenceField} = {_currentAlias}.Id)");
}
else if (node.Method.Name == "Count")
{
EmitSql(string.IsNullOrWhiteSpace(command)
? $"(SELECT COUNT({RootTableAlias}{_subQueryIndex}.Id) FROM {fieldMetadata.FieldType} {RootTableAlias}{_subQueryIndex} WHERE {RootTableAlias}{_subQueryIndex}.{referenceField} = {_currentAlias}.Id)"
: $"(SELECT COUNT({RootTableAlias}{_subQueryIndex}.Id) FROM {fieldMetadata.FieldType} {RootTableAlias}{_subQueryIndex} {string.Join(Environment.NewLine, joins.Select(x => x.ToString()))} WHERE {command} AND {RootTableAlias}{_subQueryIndex}.{referenceField} = {_currentAlias}.Id)");
}
else
{
EmitSql($"(SELECT COUNT({RootTableAlias}{_subQueryIndex}.Id) FROM {fieldMetadata.FieldType} {RootTableAlias}{_subQueryIndex} {string.Join(Environment.NewLine, joins.Select(x => x.ToString()))} WHERE {command} AND {RootTableAlias}{_subQueryIndex}.{referenceField} = {_currentAlias}.Id) = (SELECT COUNT({RootTableAlias}{_subQueryIndex}.Id) FROM {fieldMetadata.FieldType} {RootTableAlias}{_subQueryIndex} {string.Join(Environment.NewLine, joins.Select(x => x.ToString()))} WHERE {RootTableAlias}{_subQueryIndex}.{referenceField} = {_currentAlias}.Id)");
}
return(node);
}
if (node.Method.Name == "OrderBy" || node.Method.Name == "ThenBy")
{
Visit(node.Arguments[0]);
_isOrdering = true;
Visit(node.Arguments[1]);
_isOrdering = false;
EmitOrderBy($"{_currentAlias}.{_orderProperty} asc");
_orderProperty = null;
_currentAlias = RootTableAlias;
_currentEntityMetadata = _sourceEntityMetadata;
return(node);
}
if (node.Method.Name == "OrderByDescending" || node.Method.Name == "ThenByDescending")
{
Visit(node.Arguments[0]);
_isOrdering = true;
Visit(node.Arguments[1]);
_isOrdering = false;
EmitOrderBy($"{_currentAlias}.{_orderProperty} desc");
_orderProperty = null;
_currentAlias = RootTableAlias;
_currentEntityMetadata = _sourceEntityMetadata;
return(node);
}
if (node.Method.Name == "StartsWith")
{
Visit(node.Object);
var constantValue = DynamicInvokeExpression(node.Arguments[0]);
EmitSql(" LIKE ");
Parameters.Add(GetQueryParameter($"@{ParameterAlias}{ParameterAliasIndex++}", $"{constantValue}%", _currentFieldMetadata));
EmitSql(Parameters.Last().Name);
_currentAlias = RootTableAlias;
return(node);
}
if (node.Method.Name == "EndsWith")
{
Visit(node.Object);
var constantValue = DynamicInvokeExpression(node.Arguments[0]);
EmitSql(" LIKE ");
Parameters.Add(GetQueryParameter($"@{ParameterAlias}{ParameterAliasIndex++}", $"%{constantValue}", _currentFieldMetadata));
EmitSql(Parameters.Last().Name);
_currentAlias = RootTableAlias;
return(node);
}
if (node.Method.Name == "Contains")
{
Visit(node.Object);
var constantValue = DynamicInvokeExpression(node.Arguments[0]);
EmitSql(" LIKE ");
Parameters.Add(GetQueryParameter($"@{ParameterAlias}{ParameterAliasIndex++}", $"%{constantValue}%", _currentFieldMetadata));
EmitSql(Parameters.Last().Name);
_currentAlias = RootTableAlias;
return(node);
}
if (node.Method.Name == "Include")
{
Visit(node.Arguments[0]);
Includes.Add(GetIncludeMember(node.Arguments[1]));
return(node);
}
if (node.Method.Name == "Take")
{
Limit = (int)DynamicInvokeExpression(node.Arguments[1]);
return(Visit(node.Arguments[0]));
}
if (node.Method.Name == "Skip")
{
Offset = (int)DynamicInvokeExpression(node.Arguments[1]);
return(Visit(node.Arguments[0]));
}
if (node.Method.Name == "ChangeQueryType")
{
var entityType = (node.Arguments[1] as ConstantExpression).Value as Type;
_currentEntityMetadata = EntityMetadataResolver.GetEntityMetadata(entityType);
_sourceEntityMetadata = _currentEntityMetadata;
ChangedEntityType = entityType;
return(Visit(node.Arguments[0]));
}
if (node.Method.Name == "Cast")
{
return(Visit(node.Arguments[0]));
}
throw new NotSupportedException($"{node.Method.Name} is not supported.");
}
private IQuery CreateQuery(string command, Type entityType, QueryExpressionVisitor queryExpressionVisitor)
{
return(new Query(command, queryExpressionVisitor.ChangedEntityType ?? entityType,
queryExpressionVisitor.Parameters));
}