/// <summary>
/// Accept an expression visitor
/// </summary>
/// <param name="visitor">The expression visitor</param>
public virtual void Accept(IExpressionVisitor visitor)
{
if (visitor == null)
{
throw new ArgumentNullException("visitor");
}
visitor.Visit(this);
}
public override void Accept(IExpressionVisitor visitor)
{
Require.NotNull(visitor, "visitor");
visitor.Visit(this);
}
public override T Accept <T, C>(IExpressionVisitor <T, C> visitor, C context)
{
return(visitor.Visit(this, context));
}
protected virtual Expression Visit(IExpressionVisitor visitor)
{
return visitor.Visit(this);
}
public void Accept(IExpressionVisitor v)
{
v.Visit(this);
}
public override TResult Accept <TResult, TContext>(
IExpressionVisitor <TResult, TContext> visitor,
TContext environment)
{
return(visitor.Visit(this, environment));
}
//--------------------------------------------------------------------- internal override T Accept <T>(IExpressionVisitor <T> visitor) => visitor.Visit(this);
public override void Accept <T>(IExpressionVisitor <T> visitor, T context)
{
visitor.Visit(this, context);
}
public void Accept(IExpressionVisitor visitor) => visitor.Visit(this);
public void Visit(IExpressionVisitor visitor)
{
visitor.Visit(this);
}
protected internal override void AcceptVisitor(IExpressionVisitor visitor)
{
EnsureArg.IsNotNull(visitor, nameof(visitor));
visitor.Visit(this);
}
void IExpression.Accept(IExpressionVisitor visitor)
{
visitor.Visit(this);
}
public virtual TR Accept <TR>(IExpressionVisitor <TR> visitor, string context) => visitor.Visit(this, context);
protected override void OnVisit(IExpressionVisitor visitor, UpsertStatement statement)
{
if (statement.Returning != null && statement.Returning.Table != null)
{
visitor.Visit(statement.Returning.Table);
}
const string SOURCE_ALIAS = "SRC";
if (statement.Fields == null || statement.Fields.Count == 0)
{
throw new DataException("Missing required fields in the upsert statment.");
}
visitor.Output.Append("MERGE INTO ");
visitor.Visit(statement.Table);
visitor.Output.AppendLine(" USING (SELECT ");
for (int i = 0; i < statement.Values.Count; i++)
{
if (i > 0)
{
visitor.Output.Append(",");
}
visitor.Visit(statement.Values[i]);
}
visitor.Output.AppendLine(") AS " + SOURCE_ALIAS + " (");
for (int i = 0; i < statement.Fields.Count; i++)
{
if (i > 0)
{
visitor.Output.Append(",");
}
visitor.Output.Append(statement.Fields[i].Name);
}
visitor.Output.AppendLine(") ON");
for (int i = 0; i < statement.Entity.Key.Length; i++)
{
var field = Metadata.DataEntityPropertyExtension.GetFieldName(statement.Entity.Key[i], out _);
if (i > 0)
{
visitor.Output.Append(" AND ");
}
if (string.IsNullOrEmpty(statement.Table.Alias))
{
visitor.Output.Append($"{field}={SOURCE_ALIAS}.{field}");
}
else
{
visitor.Output.Append($"{statement.Table.Alias}.{field}={SOURCE_ALIAS}.{field}");
}
}
if (statement.Updation.Count > 0)
{
visitor.Output.AppendLine();
visitor.Output.Append("WHEN MATCHED");
if (statement.Where != null)
{
visitor.Output.Append(" AND ");
visitor.Visit(statement.Where);
}
visitor.Output.AppendLine(" THEN");
visitor.Output.Append("\tUPDATE SET ");
int index = 0;
foreach (var item in statement.Updation)
{
if (index++ > 0)
{
visitor.Output.Append(",");
}
visitor.Visit(item.Field);
visitor.Output.Append("=");
visitor.Visit(item.Value);
}
}
visitor.Output.AppendLine();
visitor.Output.AppendLine("WHEN NOT MATCHED THEN");
visitor.Output.Append("\tINSERT (");
for (int i = 0; i < statement.Fields.Count; i++)
{
if (i > 0)
{
visitor.Output.Append(",");
}
visitor.Output.Append(visitor.Dialect.GetIdentifier(statement.Fields[i]));
}
visitor.Output.Append(") VALUES (");
for (int i = 0; i < statement.Fields.Count; i++)
{
if (i > 0)
{
visitor.Output.Append(",");
}
visitor.Output.Append(SOURCE_ALIAS + "." + statement.Fields[i].Name);
}
visitor.Output.Append(")");
//输出返回子句
this.VisitReturning(visitor, statement.Returning);
visitor.Output.AppendLine(";");
}
public override void Accept(IExpressionVisitor visitor)
{
// using double dispatch
visitor.Visit(this);
}
protected virtual Expression Visit(IExpressionVisitor visitor)
{
return(visitor.Visit(this));
}
public virtual void Accept(IExpressionVisitor visitor)
{
visitor.Visit(this);
}
public override T Accept <T>(IExpressionVisitor <T> visitor)
{
return(visitor.Visit(this));
}
public R Accept <R, S>(IExpressionVisitor <R, S> visitor, S scope)
{
return(visitor.Visit(this, scope));
}
public override TResult Accept <TResult>(IExpressionVisitor <TResult> visitor)
{
return(visitor.Visit(this));
}
public void Accept(IExpressionVisitor <T> visitor)
{
visitor.Visit(this);
}
public override void Accept(IExpressionVisitor visitor)
{
visitor.Visit(this);
}
/// <summary>When overriden in a derived class, accepts the specified visitor.</summary>
/// <param name="visitor">The visitor to accept.</param>
protected override void AcceptCore(IExpressionVisitor visitor)
{
visitor.Visit(this);
}
public override TR Accept <TR>(IExpressionVisitor <TR> visitor, string context) => visitor.Visit(this, context);
public IExpression Accept(IExpressionVisitor visitor)
{
return(visitor.Visit(this));
}
public override void Accept(IExpressionVisitor visitor)
{
Operand.Accept(visitor);
visitor.Visit(this);
}
public void Visit(IExpressionVisitor <TContext> visitor)
{
visitor.Visit(this);
}
public override void Accept(IExpressionVisitor visitor)
{
visitor.Visit(this);
}
public override T Accept <T>(IExpressionVisitor <T> checker)
{
return(checker.Visit(this));
}
public virtual void Accept(IExpressionVisitor visitor)
{
visitor.Visit(this);
}
/// <summary>
/// Visits the <paramref name="visitor"/> based upon the type of the
/// <see cref="IExpression"/>.
/// </summary>
/// <param name="visitor">The <see cref="IIntermediateTreeVisitor"/>
/// to visit.</param>
/// <remarks>In this instance visits the <paramref name="visitor"/>
/// through <see cref="IExpressionVisitor.Visit(ITypeReferenceExpression)"/>.</remarks>
/// <exception cref="System.ArgumentNullException">thrown when <paramref name="visitor"/>
/// is null.</exception>
public void Accept(IExpressionVisitor visitor)
{
//ToDo: Fix #2.
visitor.Visit(this);
}
