/// <inheritdoc />
public override Expression VisitAlias(AliasExpression aliasExpression)
{
var validatedAlias = SpannerQueryCompilationContext.GetValidSymbol(aliasExpression.Alias);
return(base.VisitAlias(validatedAlias != aliasExpression.Alias
? new AliasExpression(validatedAlias, aliasExpression.Expression)
: aliasExpression));
}
public void AliasExpressionTest()
{
AliasMapper aliasMap = new AliasMapper();
AliasExpression expression = new AliasExpression(aliasMap);
Assert.IsTrue(expression.Match("glob is C"));
Assert.IsFalse(expression.Match("glob is N"));
expression.Execute("glob is C");
Assert.IsTrue(aliasMap.Exists("glob"));
Assert.IsTrue(String.Equals(aliasMap.GetValueForAlias("glob"), "C"));
}
public void AliasExpressionTest()
{
AliasMapper AliasMap = new AliasMapper();
AliasExpression expression = new AliasExpression(AliasMap);
Assert.True(expression.Match("glob is I"));
Assert.False(expression.Match("glob is N"));
expression.Execute("glob is I");
Assert.True(AliasMap.Exists("glob"));
Assert.Equal("I", AliasMap.GetValueForAlias("glob"));
}
Expression VisitSelectExpression(SelectExpression selectExpression)
{
base.Visit(selectExpression);
if (!RequiresRowNumberPaging(selectExpression))
{
return(selectExpression);
}
var subQuery = selectExpression.PushDownSubquery();
foreach (var projection in subQuery.Projection)
{
selectExpression.AddToProjection(projection.LiftExpressionFromSubquery(subQuery));
}
if (subQuery.OrderBy.Count == 0)
{
subQuery.AddToOrderBy(
new Ordering(new SqlFunctionExpression("@@RowCount", typeof(int)), OrderingDirection.Asc));
}
var innerRowNumberExpression = new AliasExpression(
RowNumberColumnName + (_counter != 0 ? $"{_counter}" : ""),
new RowNumberExpression_SqlServer(subQuery.OrderBy));
_counter++;
subQuery.ClearOrderBy();
subQuery.AddToProjection(innerRowNumberExpression, false);
var rowNumberReferenceExpression = new ColumnReferenceExpression(innerRowNumberExpression, subQuery);
var offset = subQuery.Offset ?? Expression.Constant(0);
if (subQuery.Offset != null)
{
selectExpression.AddToPredicate
(Expression.GreaterThan(rowNumberReferenceExpression, offset));
subQuery.Offset = null;
}
if (subQuery.Limit != null)
{
var constantValue = (subQuery.Limit as ConstantExpression)?.Value;
var offsetValue = (offset as ConstantExpression)?.Value;
var limitExpression
= constantValue != null &&
offsetValue != null
? (Expression)Expression.Constant((int)offsetValue + (int)constantValue)
: Expression.Add(offset, subQuery.Limit);
selectExpression.AddToPredicate(
Expression.LessThanOrEqual(rowNumberReferenceExpression, limitExpression));
subQuery.Limit = null;
}
return(selectExpression);
}
/// <summary>
/// 重写生成投影，对表达式重新处理。
/// </summary>
/// <param name="projection">投影表达式</param>
protected override void GenerateProjection(Expression projection)
{
try
{
if (Check.IsTraceEnabled(m_oracleLogger?.Logger))
{
Trace<DbLoggerCategory.Query>.Write(m_oracleLogger, LogLevel.Trace, OracleTraceTag.Entry, OracleTraceClassName.OracleQuerySqlGenerator, OracleTraceFuncName.GenerateProjection);
}
AliasExpression aliasExpression = projection as AliasExpression;
Expression expressionProcess = aliasExpression?.Expression ?? projection;
Expression updatedExperssion = ExplicitCastToBool(expressionProcess);
expressionProcess = aliasExpression != null
? new AliasExpression(aliasExpression.Alias, updatedExperssion)
: updatedExperssion;
// 此处会调用OracleSqlGenerationHelper中方法改写表达式，例如为表和字段加上引号等
base.GenerateProjection(expressionProcess);
if (is112SqlCompatibility && outerSelectRequired)
{
if (!(projection is AliasExpression))
{
Sql.Append(" K" + generateProjectionCallCountCounter);
}
generateProjectionCallCountCounter++;
}
}
catch (Exception ex)
{
if (Check.IsErrorEnabled(m_oracleLogger?.Logger))
{
Trace<DbLoggerCategory.Query>.Write(m_oracleLogger, LogLevel.Error, OracleTraceTag.Error, OracleTraceClassName.OracleQuerySqlGenerator, OracleTraceFuncName.GenerateProjection, ex.ToString());
}
throw;
}
finally
{
if (Check.IsTraceEnabled(m_oracleLogger?.Logger))
{
Trace<DbLoggerCategory.Query>.Write(m_oracleLogger, LogLevel.Trace, OracleTraceTag.Exit, OracleTraceClassName.OracleQuerySqlGenerator, OracleTraceFuncName.GenerateProjection);
}
}
}
public override Expression VisitAlias(AliasExpression aliasExpression)
{
Check.NotNull(aliasExpression, nameof(aliasExpression));
Visit(aliasExpression.Expression);
if (aliasExpression.Alias != null)
{
Sql.Append(" ");
}
if (aliasExpression.Alias != null)
{
Sql.Append(SqlGenerator.DelimitIdentifier(aliasExpression.Alias));
}
return(aliasExpression);
}
public virtual Expression VisitAliasExpression(AliasExpression aliasExpression)
{
Check.NotNull(aliasExpression, nameof(aliasExpression));
if (!aliasExpression.Projected)
{
VisitExpression(aliasExpression.Expression);
if (aliasExpression.Alias != null)
{
_sql.Append(" AS ");
}
}
if (aliasExpression.Alias != null)
{
_sql.Append(DelimitIdentifier(aliasExpression.Alias));
}
return(aliasExpression);
}
public virtual Expression VisitAlias(AliasExpression aliasExpression)
{
Check.NotNull(aliasExpression, nameof(aliasExpression));
if (!aliasExpression.Projected)
{
Visit(aliasExpression.Expression);
if (aliasExpression.Alias != null)
{
_relationalCommandBuilder.Append(" AS ");
}
}
if (aliasExpression.Alias != null)
{
_relationalCommandBuilder.Append(_sqlGenerationHelper.DelimitIdentifier(aliasExpression.Alias));
}
return(aliasExpression);
}
protected override void GenerateProjection(Expression projection)
{
try
{
if (m_oracleLogger != null && m_oracleLogger.Logger != null && m_oracleLogger.Logger.IsEnabled(LogLevel.Trace))
{
Trace <DbLoggerCategory.Query> .Write(m_oracleLogger, LogLevel.Trace, OracleTraceTag.Entry, OracleTraceClassName.OracleQuerySqlGenerator, OracleTraceFuncName.GenerateProjection);
}
AliasExpression aliasExpression = projection as AliasExpression;
Expression expression = aliasExpression?.Expression ?? projection;
Expression expression2 = ExplicitCastToBool(expression);
expression = ((aliasExpression != null) ? new AliasExpression(aliasExpression.Alias, expression2) : expression2);
base.GenerateProjection(expression);
if (is112SqlCompatibility && outerSelectRequired)
{
if (!(projection is AliasExpression))
{
Sql.Append(" K" + generateProjectionCallCountCounter);
}
generateProjectionCallCountCounter++;
}
}
catch (Exception ex)
{
if (m_oracleLogger != null && m_oracleLogger.Logger != null && m_oracleLogger.Logger.IsEnabled(LogLevel.Error))
{
Trace <DbLoggerCategory.Query> .Write(m_oracleLogger, LogLevel.Error, OracleTraceTag.Error, OracleTraceClassName.OracleQuerySqlGenerator, OracleTraceFuncName.GenerateProjection, ex.ToString());
}
throw;
}
finally
{
if (m_oracleLogger != null && m_oracleLogger.Logger != null && m_oracleLogger.Logger.IsEnabled(LogLevel.Trace))
{
Trace <DbLoggerCategory.Query> .Write(m_oracleLogger, LogLevel.Trace, OracleTraceTag.Exit, OracleTraceClassName.OracleQuerySqlGenerator, OracleTraceFuncName.GenerateProjection);
}
}
}
Expression VisitSelectExpression(SelectExpression selectExpression)
{
base.Visit(selectExpression);
if (!RequiresRowNumberPaging(selectExpression))
{
return(selectExpression);
}
SelectExpression selectExpression2 = selectExpression.PushDownSubquery();
foreach (Expression item in selectExpression2.Projection)
{
selectExpression.AddToProjection(item.LiftExpressionFromSubquery(selectExpression2), true);
}
AliasExpression aliasExpression = new AliasExpression("row_number" + ((_counter != 0) ? $"{_counter}" : ""), new RowNumberExpression_DB2(selectExpression2.OrderBy));
_counter++;
selectExpression2.ClearOrderBy();
selectExpression2.AddToProjection(aliasExpression, false);
ColumnReferenceExpression left = new ColumnReferenceExpression(aliasExpression, selectExpression2);
Expression expression = selectExpression2.Offset ?? Expression.Constant(0);
if (selectExpression2.Offset != null)
{
selectExpression.AddToPredicate(Expression.GreaterThan(left, expression));
selectExpression2.Offset = null;
}
if (selectExpression2.Limit != null)
{
object obj = (selectExpression2.Limit as ConstantExpression)?.Value;
object obj2 = (expression as ConstantExpression)?.Value;
Expression right = (obj != null && obj2 != null) ? ((Expression)Expression.Constant((int)obj2 + (int)obj)) : ((Expression)Expression.Add(expression, selectExpression2.Limit));
selectExpression.AddToPredicate(Expression.LessThanOrEqual(left, right));
selectExpression2.Limit = null;
}
return(selectExpression);
}
public static ColumnExpression TryGetColumnExpression([NotNull] this AliasExpression aliasExpression) => aliasExpression.Expression as ColumnExpression;
public static bool HasColumnExpression([CanBeNull] this AliasExpression aliasExpression) => aliasExpression?.Expression is ColumnExpression;
private Expression VisitSelectExpression(SelectExpression selectExpression)
{
base.Visit(selectExpression);
if (!RequiresRowNumberPaging(selectExpression))
{
return(selectExpression);
}
var subQuery = selectExpression.PushDownSubquery();
foreach (var projection in subQuery.Projection)
{
var alias = projection as AliasExpression;
var column = projection as ColumnExpression;
if (column != null)
{
column = new ColumnExpression(column.Name, column.Property, subQuery);
selectExpression.AddToProjection(column);
continue;
}
column = alias?.TryGetColumnExpression();
if (column != null)
{
column = new ColumnExpression(column.Name, column.Property, subQuery);
alias = new AliasExpression(alias.Alias, column);
selectExpression.AddToProjection(alias);
}
else
{
column = new ColumnExpression(alias.Alias, alias.Expression.Type, subQuery);
selectExpression.AddToProjection(column);
}
}
if (subQuery.OrderBy.Count == 0)
{
subQuery.AddToOrderBy(
new Ordering(new SqlFunctionExpression("@@RowCount", typeof(int)), OrderingDirection.Asc));
}
var columnExpression = new ColumnExpression(RowNumberColumnName, typeof(int), subQuery);
var rowNumber = new RowNumberExpression(columnExpression, subQuery.OrderBy);
subQuery.ClearOrderBy();
subQuery.AddToProjection(rowNumber, false);
Expression predicate = null;
var offset = subQuery.Offset ?? Expression.Constant(0);
if (subQuery.Offset != null)
{
predicate = Expression.GreaterThan(columnExpression, offset);
}
if (subQuery.Limit != null)
{
var constantValue = (subQuery.Limit as ConstantExpression)?.Value;
var offsetValue = (offset as ConstantExpression)?.Value;
var limitExpression
= constantValue != null &&
offsetValue != null
? (Expression)Expression.Constant((int)offsetValue + (int)constantValue)
: Expression.Add(offset, subQuery.Limit);
var expression = Expression.LessThanOrEqual(columnExpression, limitExpression);
if (predicate != null)
{
expression = Expression.AndAlso(predicate, expression);
}
predicate = expression;
}
selectExpression.Predicate = predicate;
return(selectExpression);
}
private Expression VisitSelectExpression(SelectExpression selectExpression)
{
base.Visit(selectExpression);
if (!RequiresRowNumberPaging(selectExpression))
{
return(selectExpression);
}
var projections = new List <Expression>();
projections.AddRange(selectExpression.Projection);
var subQuery = selectExpression.PushDownSubquery();
foreach (var projection in projections)
{
var alias = projection as AliasExpression;
var column = projection as ColumnExpression;
if (column != null)
{
column = new ColumnExpression(column.Name, column.Property, subQuery);
selectExpression.AddToProjection(column);
continue;
}
column = alias?.TryGetColumnExpression();
if (column != null)
{
column = new ColumnExpression(column.Name, column.Property, subQuery);
alias = new AliasExpression(alias.Alias, column);
selectExpression.AddToProjection(alias);
}
else
{
selectExpression.AddToProjection(projection);
}
}
if (subQuery.OrderBy.Count == 0)
{
subQuery.AddToOrderBy(
new Ordering(new SqlFunctionExpression("@@RowCount", typeof(int)), OrderingDirection.Asc));
}
var columnExpression = new ColumnExpression(RowNumberColumnName, typeof(int), subQuery);
var rowNumber = new RowNumberExpression(columnExpression, subQuery.OrderBy);
subQuery.ClearOrderBy();
subQuery.ClearProjection();
subQuery.AddToProjection(rowNumber);
subQuery.IsProjectStar = true;
Expression predicate = null;
var offset = subQuery.Offset ?? 0;
if (subQuery.Offset.HasValue)
{
predicate = Expression.GreaterThan(columnExpression, Expression.Constant(offset));
}
if (subQuery.Limit.HasValue)
{
var exp = Expression.LessThanOrEqual(columnExpression, Expression.Constant(offset + subQuery.Limit.Value));
if (predicate != null)
{
exp = Expression.AndAlso(predicate, exp);
}
predicate = exp;
}
selectExpression.Predicate = predicate;
return(selectExpression);
}
protected virtual Expression VisitAlias(AliasExpression node)
{
Visit(node.From);
Visit(node.To);
return(node);
}
