Deveel.Data.Sql.Expressions.SqlExpressionExtensions Class Reference

Extension methods to SqlExpression More...

Static Public Member Functions
static ObjectName	AsReferenceName (this SqlExpression expression)
	Extracts the name of the reference from the expression. More...
static IQueryPlanNode	AsQueryPlan (this SqlExpression expression)
static DataObject	EvaluateToConstant (this SqlExpression expression, EvaluateContext context)
	Evaluates the expression and reduces to a constant expression, whose value is then returned. More...
static DataObject	EvaluateToConstant (this SqlExpression expression, IRequest request, IVariableResolver variableResolver)
static SqlType	ReturnType (this SqlExpression expression, IRequest query, IVariableResolver variableResolver)
	Gets the return type of the expression when evaluated. More...
static bool	HasAggregate (this SqlExpression expression, IRequest query)
	Verifies if the expression contains any aggregate function in the tree. More...
static bool	IsConstant (this SqlExpression expression)

Detailed Description

Extension methods to SqlExpression

Definition at line 28 of file SqlExpressionExtensions.cs.

Member Function Documentation

static IQueryPlanNode Deveel.Data.Sql.Expressions.SqlExpressionExtensions.AsQueryPlan ( this SqlExpression  expression )

inlinestatic

Definition at line 45 of file SqlExpressionExtensions.cs.

                                                                                {
            var constantExp = expression as SqlConstantExpression;
            if (constantExp == null)
                return null;

            var value = constantExp.Value;
            if (value.Value is SqlQueryObject)
                return ((SqlQueryObject) value.Value).QueryPlan;

            return null;
        }

static ObjectName Deveel.Data.Sql.Expressions.SqlExpressionExtensions.AsReferenceName ( this SqlExpression  expression )

inlinestatic

Extracts the name of the reference from the expression.

Parameters

expression

The expression that encapsulates the reference

Returns

Returns an ObjectName instance if the given expression is a SqlReferenceExpression, otherwise it returns null.

Definition at line 37 of file SqlExpressionExtensions.cs.

                                                                                {
            var refExpression = expression as SqlReferenceExpression;
            if (refExpression == null)
                return null;

            return refExpression.ReferenceName;
        }

static DataObject Deveel.Data.Sql.Expressions.SqlExpressionExtensions.EvaluateToConstant ( this SqlExpression  expression, EvaluateContext  context  )

inlinestatic

Evaluates the expression and reduces to a constant expression, whose value is then returned.

Parameters

expression	The expression to evaluate.
context	The context used to evaluate the expression.

Returns

Returns a DataObject is the result of the SqlExpression.Evaluate(Deveel.Data.Sql.Expressions.EvaluateContext) is a SqlConstantExpression.

Exceptions

InvalidOperationException

If the expression could not be evaluated or if the result of the evaluation is not a SqlConstantExpression.

See also

SqlExpression.Evaluate(Deveel.Data.Sql.Expressions.EvaluateContext), SqlConstantExpression, SqlConstantExpression.Value

Definition at line 75 of file SqlExpressionExtensions.cs.

                                                                                                            {
            var evalExp = expression.Evaluate(context);
            if (evalExp == null)
                throw new InvalidOperationException();

            var constantExp = evalExp as SqlConstantExpression;
            if (constantExp == null)
                throw new InvalidOperationException();

            return constantExp.Value;
        }

static DataObject Deveel.Data.Sql.Expressions.SqlExpressionExtensions.EvaluateToConstant ( this SqlExpression  expression, IRequest  request, IVariableResolver  variableResolver  )

inlinestatic

Definition at line 87 of file SqlExpressionExtensions.cs.

                                                                                                                                         {
            return expression.EvaluateToConstant(new EvaluateContext(request, variableResolver));
        }

static bool Deveel.Data.Sql.Expressions.SqlExpressionExtensions.HasAggregate ( this SqlExpression  expression, IRequest  query  )

inlinestatic

Verifies if the expression contains any aggregate function in the tree.

Parameters

expression	The expression to verify.
query

Returns

Returns true if the expression has any aggregate function in its tree, or false otherwise.

Definition at line 118 of file SqlExpressionExtensions.cs.

                                                                                       {
            var visitor = new AggregateChecker(query);
            return visitor.HasAggregate(expression);
        }

static bool Deveel.Data.Sql.Expressions.SqlExpressionExtensions.IsConstant ( this SqlExpression  expression )

inlinestatic

Definition at line 123 of file SqlExpressionExtensions.cs.

                                                                     {
            var visitor = new ConstantVisitor();
            visitor.Visit(expression);
            return visitor.IsConstant;
        }

static SqlType Deveel.Data.Sql.Expressions.SqlExpressionExtensions.ReturnType ( this SqlExpression  expression, IRequest  query, IVariableResolver  variableResolver  )

inlinestatic

Gets the return type of the expression when evaluated.

Parameters

expression	The expression to check.
query	The query context used to evaluate the return type of the expression.
variableResolver	The object used to resolve variable references in the expression tree.

Returns

Returns the SqlType that an evaluation of the expression would return, or null if the final result of the evaluation has no return type.

Definition at line 103 of file SqlExpressionExtensions.cs.

                                                                                                                            {
            var visitor = new ReturnTypeVisitor(query, variableResolver);
            return visitor.GetType(expression);
        }

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The documentation for this class was generated from the following file:

• /var/calculate/remote/distfiles/egit-src/deveeldb.git/src/deveeldb/Deveel.Data.Sql.Expressions/SqlExpressionExtensions.cs