public LimitingDataReader(IDataReader innerReader, LimitingDataReaderMode mode)
{
if (innerReader == null)
throw new ArgumentNullException("innerReader");
mInnerReader = innerReader;
mMode = mode;
}
public LimitingDataReader(IDataReader innerReader, LimitingDataReaderMode mode)
{
if (innerReader == null)
{
throw new ArgumentNullException("innerReader");
}
mInnerReader = innerReader;
mMode = mode;
}
protected override void OnBeginVisitExpression(Expression node)
{
mIsInnerCall = true;
mText.Length = 0;
mParameters.Clear();
mIsSequence = true;
mLimitingDataReaderMode = LimitingDataReaderMode.None;
mElementType = null;
mProperties.Clear();
}
protected override void OnBeginVisitExpression(Expression node)
{
mIsInnerCall = true;
mText.Length = 0;
mParameters.Clear();
mIsSequence = true;
mLimitingDataReaderMode = LimitingDataReaderMode.None;
mElementType = null;
mProperties.Clear();
}
protected override Expression VisitConstant(ConstantExpression node)
{
if (node.IsQueryable())
{
mLimitingDataReaderMode = LimitingDataReaderMode.None;
mIsSequence = true;
mElementType = TypeSystem.GetElementType(node.Type);
var schema = @"dbo";
var table = mElementType.Name;
var tableAttributes = mElementType.GetCustomAttributes(typeof(TableAttribute), true).Cast <TableAttribute>();
foreach (var tableAttribute in tableAttributes)
{
if (!string.IsNullOrEmpty(tableAttribute.SchemaName))
{
schema = tableAttribute.SchemaName;
}
if (!string.IsNullOrEmpty(tableAttribute.Name))
{
table = tableAttribute.Name;
}
}
mText.Append(@"SELECT");
var separator = @" ";
var properties = mElementType.GetProperties(BindingFlags.Public | BindingFlags.Instance)
.Where(a => a.CanRead && a.CanWrite);
foreach (var property in properties)
{
mProperties.Add(property);
var column = GetColumnName(property);
mText.Append(separator);
mText.Append(EncodeSqlName(column));
separator = @", ";
}
mText.Append(@" FROM ");
mText.Append(EncodeSqlName(schema));
mText.Append(@".");
mText.Append(EncodeSqlName(table));
}
else
{
mText.Append(node.Value.ToSqlConstant());
}
return(base.VisitConstant(node));
}
protected override Expression VisitMethodCall(MethodCallExpression node)
{
if (node.Method.Name == "Where")
{
mText.Append(@"SELECT * FROM (");
base.Visit(node.Arguments[0]);
mText.Append(@") AS temp WHERE ");
var lambda = (LambdaExpression)StripQuotes(node.Arguments[1]);
base.Visit(lambda.Body);
return(node);
}
if (node.Method.Name == "First" || node.Method.Name == "FirstOrDefault")
{
mText.Append(@"SELECT TOP 1 * FROM (");
var resultingNode = base.VisitMethodCall(node);
mText.Append(@") AS temp");
mIsSequence = false;
mLimitingDataReaderMode = node.Method.Name == "First" ? LimitingDataReaderMode.AtLeastOneRow : LimitingDataReaderMode.None;
mElementType = TypeSystem.GetElementType(node.Type);
return(resultingNode);
}
if (node.Method.Name == "Single" || node.Method.Name == "SingleOrDefault")
{
mText.Append(@"SELECT TOP 2 * FROM (");
var resultingNode = base.VisitMethodCall(node);
mText.Append(@") AS temp");
mIsSequence = false;
mLimitingDataReaderMode = (node.Method.Name == "Single" ? LimitingDataReaderMode.AtLeastOneRow : LimitingDataReaderMode.None) | LimitingDataReaderMode.AtMostOneRow;
mElementType = TypeSystem.GetElementType(node.Type);
return(resultingNode);
}
throw new InvalidOperationException(string.Format("Method [{0}] is unsupported.", node.Method.Name));
}
protected override Expression VisitMethodCall(MethodCallExpression node)
{
if (node.Method.Name == "Where")
{
mText.Append(@"SELECT * FROM (");
base.Visit(node.Arguments[0]);
mText.Append(@") AS temp WHERE ");
var lambda = (LambdaExpression)StripQuotes(node.Arguments[1]);
base.Visit(lambda.Body);
return node;
}
if (node.Method.Name == "First" || node.Method.Name == "FirstOrDefault")
{
mText.Append(@"SELECT TOP 1 * FROM (");
var resultingNode = base.VisitMethodCall(node);
mText.Append(@") AS temp");
mIsSequence = false;
mLimitingDataReaderMode = node.Method.Name == "First" ? LimitingDataReaderMode.AtLeastOneRow : LimitingDataReaderMode.None;
mElementType = TypeSystem.GetElementType(node.Type);
return resultingNode;
}
if (node.Method.Name == "Single" || node.Method.Name == "SingleOrDefault")
{
mText.Append(@"SELECT TOP 2 * FROM (");
var resultingNode = base.VisitMethodCall(node);
mText.Append(@") AS temp");
mIsSequence = false;
mLimitingDataReaderMode = (node.Method.Name == "Single" ? LimitingDataReaderMode.AtLeastOneRow : LimitingDataReaderMode.None) | LimitingDataReaderMode.AtMostOneRow;
mElementType = TypeSystem.GetElementType(node.Type);
return resultingNode;
}
throw new InvalidOperationException(string.Format("Method [{0}] is unsupported.", node.Method.Name));
}
protected override Expression VisitConstant(ConstantExpression node)
{
if (node.IsQueryable())
{
mLimitingDataReaderMode = LimitingDataReaderMode.None;
mIsSequence = true;
mElementType = TypeSystem.GetElementType(node.Type);
var schema = @"dbo";
var table = mElementType.Name;
var tableAttributes = mElementType.GetCustomAttributes(typeof(TableAttribute), true).Cast<TableAttribute>();
foreach (var tableAttribute in tableAttributes)
{
if (!string.IsNullOrEmpty(tableAttribute.SchemaName))
schema = tableAttribute.SchemaName;
if (!string.IsNullOrEmpty(tableAttribute.Name))
table = tableAttribute.Name;
}
mText.Append(@"SELECT");
var separator = @" ";
var properties = mElementType.GetProperties(BindingFlags.Public | BindingFlags.Instance)
.Where(a => a.CanRead && a.CanWrite);
foreach (var property in properties)
{
mProperties.Add(property);
var column = GetColumnName(property);
mText.Append(separator);
mText.Append(EncodeSqlName(column));
separator = @", ";
}
mText.Append(@" FROM ");
mText.Append(EncodeSqlName(schema));
mText.Append(@".");
mText.Append(EncodeSqlName(table));
}
else
{
mText.Append(node.Value.ToSqlConstant());
}
return base.VisitConstant(node);
}
