public virtual Expression VisitIsNullExpression(IsNullExpression isNullExpression)
{
Check.NotNull(isNullExpression, "isNullExpression");
VisitExpression(isNullExpression.Operand);
_sql.Append(" IS NULL");
return(isNullExpression);
}
public virtual Expression VisitIsNotNull([NotNull] IsNullExpression isNotNullExpression)
{
Check.NotNull(isNotNullExpression, nameof(isNotNullExpression));
Visit(isNotNullExpression.Operand);
_sql.Append(" IS NOT NULL");
return(isNotNullExpression);
}
public virtual Expression VisitIsNotNull([NotNull] IsNullExpression isNotNullExpression)
{
Check.NotNull(isNotNullExpression, nameof(isNotNullExpression));
Visit(isNotNullExpression.Operand);
_relationalCommandBuilder.Append(" IS NOT NULL");
return(isNotNullExpression);
}
protected internal virtual Expression VisitIsNull(IsNullExpression isNull)
{
var newExpr = Visit(isNull.Expression);
if (newExpr != isNull.Expression)
{
return(new IsNullExpression(newExpr));
}
return(isNull);
}
/// <summary>
/// 访问IsNull表达式。
/// </summary>
/// <param name="isNullExpression">表达式实例。</param>
/// <returns>返回访问后的表达式实例对象。</returns>
public virtual Expression VisitIsNull(IsNullExpression isNullExpression)
{
Check.NotNull(isNullExpression, nameof(isNullExpression));
Visit(isNullExpression.Operand);
_builder.Append(" IS NULL");
return(isNullExpression);
}
public override ISqlElement VisitIsNullExpression(IsNullExpression expression)
{
Visit(expression.Argument);
builder.Append(" is ");
if (expression.IsNotNull)
{
builder.Append("not ");
}
builder.Append("null");
return(expression);
}
protected override Expression VisitIsNull(IsNullExpression isnull)
{
this.VisitValue(isnull.Expression);
if (isnull.IsNot)
{
sb.Append(" IS NOT NULL");
}
else
{
sb.Append(" IS NULL");
}
return(isnull);
}
protected override Expression VisitIsNull(IsNullExpression isnull)
{
this.VisitValue(isnull.Expression);
if (isnull.Not)
sb.Append(" IS NOT NULL");
else
sb.Append(" IS NULL");
return isnull;
}
public virtual ISqlElement VisitIsNullExpression(IsNullExpression expression)
{
expression.Argument = Visit(expression.Argument);
return(expression);
}
protected virtual bool CompareIsNull(IsNullExpression a, IsNullExpression b)
{
return(Compare(a.Expression, b.Expression));
}
public override void Visit(IsNullExpression expression)
{
_expressionString.Append(" ISNULL(");
Visit(expression.Property);
_expressionString.Append(") ");
}
protected virtual Expression VisitIsNull(IsNullExpression isnull)
{
var expr = this.Visit(isnull.Expression);
return this.UpdateIsNull(isnull, expr);
}
protected virtual bool CompareIsNull(IsNullExpression a, IsNullExpression b)
{
return this.Compare(a.Expression, b.Expression);
}
protected virtual Expression VisitIsNull(IsNullExpression isNull)
{
var newExpr = Visit(isNull.Expression);
if (newExpr != isNull.Expression)
return new IsNullExpression(newExpr);
return isNull;
}
protected override Expression VisitIsNull(IsNullExpression isnull)
{
VisitValue(isnull.Expression);
sb.Append(" IS NULL");
return isnull;
}
private bool CompareIsNull(IsNullExpression a, IsNullExpression b)
{
return this.Compare(a.Expression, b.Expression);
}
protected override Expression VisitIsNull(IsNullExpression isNull)
{
var newExpr = MakeSqlValue(Visit(isNull.Expression));
if (newExpr != isNull.Expression)
return new IsNullExpression(newExpr);
return isNull;
}
protected Expression MakeIsNull(Expression expression, bool negate)
{
Expression isnull = new IsNullExpression(expression);
return negate ? Expression.Not(isnull) : isnull;
}
/// <summary>
/// Visits the is null.
/// </summary>
/// <param name="isnull">The isnull.</param>
/// <returns></returns>
protected override Expression VisitIsNull(IsNullExpression isnull)
{
this.VisitValue(isnull.Expression);
this.Write(" IS NULL");
return(isnull);
}
protected virtual Expression VisitIsNull(IsNullExpression isnull)
{
Expression expr = this.Visit(isnull.Expression);
if (expr != isnull.Expression)
{
return new IsNullExpression(expr);
}
return isnull;
}
protected IsNullExpression UpdateIsNull(IsNullExpression isnull, Expression expression)
{
if (expression != isnull.Expression)
{
return new IsNullExpression(expression);
}
return isnull;
}
protected override Expression VisitIsNull(IsNullExpression isnull)
{
this.VisitValue(isnull.Expression);
this.Write(" IS NULL");
return isnull;
}
protected override Expression VisitIsNull(IsNullExpression isNull)
{
sb.Append("(");
this.Visit(isNull.Expression);
sb.Append(") IS NULL");
return isNull;
}
