private void VisitBinary(DbBinaryExpression expression, string separator)
{
commandText.Append("(");
expression.Left.Accept(this);
commandText.Append(separator);
expression.Right.Accept(this);
commandText.Append(")");
}
private void VisitBinary(DbBinaryExpression expr)
{
VisitExprKind(expr.ExpressionKind);
_key.Append('(');
expr.Left.Accept(this);
_key.Append(',');
expr.Right.Accept(this);
_key.Append(')');
}
protected virtual void VisitBinary(DbBinaryExpression expression)
{
if (expression == null) throw new ArgumentException("expression");
this.VisitExpression(expression.Left);
this.VisitExpression(expression.Right);
}
private void ValidateBinaryExpression(DbBinaryExpression binaryExpression, DbBinaryExpressionType binaryExpressionType)
{
Assert.IsNotNull(binaryExpression);
Assert.IsNotNull(binaryExpression.LeftExpression);
Assert.IsNotNull(binaryExpression.RightExpression);
Assert.IsTrue(binaryExpression.ExpressionType == DbExpressionType.Binary);
Assert.IsTrue(binaryExpression.BinaryExpressionType == binaryExpressionType);
}
private void BeginBinary(DbBinaryExpression e)
{
Begin(e);
Begin("Left");
Dump(e.Left);
End("Left");
Begin("Right");
Dump(e.Right);
End("Right");
}
public static bool ExpressionEquals(DbBinaryExpression exp1, DbBinaryExpression exp2)
{
if (exp1.Method != exp2.Method)
return false;
if (!EqualsCompare(exp1.Left, exp2.Left))
return false;
if (!EqualsCompare(exp1.Right, exp2.Right))
return false;
return true;
}
/// <summary> /// Visits the <see cref="DbBinaryExpression"/>. /// </summary> /// <param name="expression">The expression.</param> public abstract void Visit(DbBinaryExpression expression);
static void StringConcat(DbBinaryExpression exp, SqlGenerator generator)
{
List <DbExpression> operands = new List <DbExpression>();
operands.Add(exp.Right);
DbExpression left = exp.Left;
DbAddExpression e = null;
while ((e = (left as DbAddExpression)) != null && (e.Method == UtilConstants.MethodInfo_String_Concat_String_String || e.Method == UtilConstants.MethodInfo_String_Concat_Object_Object))
{
operands.Add(e.Right);
left = e.Left;
}
operands.Add(left);
DbExpression whenExp = null;
List <DbExpression> operandExps = new List <DbExpression>(operands.Count);
for (int i = operands.Count - 1; i >= 0; i--)
{
DbExpression operand = operands[i];
DbExpression opBody = operand;
if (opBody.Type != UtilConstants.TypeOfString)
{
// 需要 cast type
opBody = DbExpression.Convert(opBody, UtilConstants.TypeOfString);
}
DbExpression equalNullExp = DbExpression.Equal(opBody, UtilConstants.DbConstant_Null_String);
if (whenExp == null)
{
whenExp = equalNullExp;
}
else
{
whenExp = DbExpression.And(whenExp, equalNullExp);
}
operandExps.Add(opBody);
}
generator._sqlBuilder.Append("CASE", " WHEN ");
whenExp.Accept(generator);
generator._sqlBuilder.Append(" THEN ");
DbConstantExpression.Null.Accept(generator);
generator._sqlBuilder.Append(" ELSE ");
generator._sqlBuilder.Append("(");
for (int i = 0; i < operandExps.Count; i++)
{
if (i > 0)
{
generator._sqlBuilder.Append(" || ");
}
generator._sqlBuilder.Append("IFNULL(");
operandExps[i].Accept(generator);
generator._sqlBuilder.Append(",");
DbConstantExpression.StringEmpty.Accept(generator);
generator._sqlBuilder.Append(")");
}
generator._sqlBuilder.Append(")");
generator._sqlBuilder.Append(" END");
}
/// <summary>
/// Constructs a new pattern that is matched iff the argument expression is a <see cref="DbBinaryExpression"/> with left and right subexpressions that match the corresponding <paramref name="leftPattern"/> and <paramref name="rightPattern"/> patterns
/// </summary>
internal static Func <DbExpression, bool> MatchBinary(Func <DbExpression, bool> leftPattern, Func <DbExpression, bool> rightPattern)
{
return(e => { DbBinaryExpression binEx = (e as DbBinaryExpression); return (binEx != null && leftPattern(binEx.Left) && rightPattern(binEx.Right)); });
}
