Deveel.Data.Sql.Query.RangeSelectNode Class Reference

The node for performing a simple indexed query on a single column of the child node. More...

Inheritance diagram for Deveel.Data.Sql.Query.RangeSelectNode:

Classes
class	RangeSetCalculator
class	RangeSetUpdater

Public Member Functions
	RangeSelectNode (IQueryPlanNode child, SqlExpression expression)
override ITable	Evaluate (IRequest context)

Protected Member Functions
override void	GetData (SerializeData data)
Protected Member Functions inherited from Deveel.Data.Sql.Query.SingleQueryPlanNode
	SingleQueryPlanNode (IQueryPlanNode child)
	SingleQueryPlanNode (ObjectData data)

Properties
SqlExpression	Expression [get, private set]
	A simple expression that represents the range to select. See the class comments for a description for how this expression must be formed. More...
Properties inherited from Deveel.Data.Sql.Query.SingleQueryPlanNode
IQueryPlanNode	Child [get, private set]
	Gets the single child node of the plan. More...

Private Member Functions
	RangeSelectNode (ObjectData data)

Detailed Description

The node for performing a simple indexed query on a single column of the child node.

Finds the set from the child node that matches the range.

The given Expression object must conform to a number of rules. It may reference only one column in the child node. It must consist of only simple mathemetical and logical operators (<, >, =, <>, >=, <=, AND, OR). The left side of each mathematical operator must be a variable, and the right side must be a constant (parameter subsitution or correlated value).

Breaking any of these rules will mean the range select can not happen.

For example:

(col > 10 AND col < 100) OR col > 1000 OR col == 10

Definition at line 53 of file RangeSelectNode.cs.

Constructor & Destructor Documentation

Deveel.Data.Sql.Query.RangeSelectNode.RangeSelectNode ( IQueryPlanNode  child, SqlExpression  expression  )

inline

Definition at line 54 of file RangeSelectNode.cs.

            : base(child) {
            Expression = expression;
        }

Deveel.Data.Sql.Query.RangeSelectNode.RangeSelectNode ( ObjectData  data )

inlineprivate

Definition at line 59 of file RangeSelectNode.cs.

            : base(data) {
            Expression = data.GetValue<SqlExpression>("Expression");
        }

Member Function Documentation

override ITable Deveel.Data.Sql.Query.RangeSelectNode.Evaluate ( IRequest  context )

inlinevirtual

Implements Deveel.Data.Sql.Query.SingleQueryPlanNode.

Definition at line 76 of file RangeSelectNode.cs.

                                                          {
            var t = Child.Evaluate(context);

            var exp = Expression;

            // Assert that all variables in the expression are identical.
            var columnNames = exp.DiscoverReferences();
            ObjectName columnName = null;
            foreach (var cv in columnNames) {
                if (columnName != null && !cv.Equals(columnName))
                    throw new InvalidOperationException("Range plan does not contain common column.");

                columnName = cv;
            }

            // Find the variable field in the table.
            var col = t.IndexOfColumn(columnName);
            if (col == -1)
                throw new InvalidOperationException("Could not find column reference in table: " + columnName);

            var field = t.TableInfo[col];

            // Calculate the range
            var range = new IndexRangeSet();
            var calculator = new RangeSetCalculator(context, field, range);
            range = calculator.Calculate(exp);

            // Select the range from the table
            var ranges = range.ToArray();
            return t.SelectRange(columnName, ranges);
        }

override void Deveel.Data.Sql.Query.RangeSelectNode.GetData ( SerializeData  data )

inlineprotectedvirtual

Reimplemented from Deveel.Data.Sql.Query.SingleQueryPlanNode.

Definition at line 71 of file RangeSelectNode.cs.

                                                            {
            data.SetValue("Expression", Expression);
        }

Property Documentation

SqlExpression Deveel.Data.Sql.Query.RangeSelectNode.Expression

getprivate set

A simple expression that represents the range to select. See the class comments for a description for how this expression must be formed.

Definition at line 69 of file RangeSelectNode.cs.

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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.Query/RangeSelectNode.cs