The type of the link. For example, in Hash Joins this could be used to
distinguish between the build child and the probe child, or in the case
of the child being an output variable, to represent the tag associated
with the output variable.
Only present if the child node is [SCALAR][google.spanner.v1.PlanNode.Kind.SCALAR] and corresponds
to an output variable of the parent node. The field carries the name of
the output variable.
For example, a TableScan operator that reads rows from a table will
have child links to the SCALAR nodes representing the output variables
created for each column that is read by the operator. The corresponding
variable fields will be set to the variable names assigned to the
columns.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-07 UTC."],[[["\u003cp\u003eThe latest beta version for \u003ccode\u003eGoogle.Cloud.Spanner.V1\u003c/code\u003e is \u003ccode\u003e5.0.0-beta05\u003c/code\u003e, with multiple previous beta and stable versions available, starting from version \u003ccode\u003e3.5.0\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003eChildLink\u003c/code\u003e is a class that describes metadata for parent-child relationships within a \u003ccode\u003ePlanNode\u003c/code\u003e in \u003ccode\u003eGoogle.Cloud.Spanner.V1\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eChildLink\u003c/code\u003e class implements several interfaces including \u003ccode\u003eIMessage\u003c/code\u003e, \u003ccode\u003eIEquatable\u003c/code\u003e, \u003ccode\u003eIDeepCloneable\u003c/code\u003e, and \u003ccode\u003eIBufferMessage\u003c/code\u003e, and inherits members from the \u003ccode\u003eObject\u003c/code\u003e class.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003eChildLink\u003c/code\u003e contains properties such as \u003ccode\u003eChildIndex\u003c/code\u003e, \u003ccode\u003eType\u003c/code\u003e, and \u003ccode\u003eVariable\u003c/code\u003e which represent the child node's index, the link type, and the variable name if it's a scalar output, respectively.\u003c/p\u003e\n"],["\u003cp\u003eIt offers two constructors: one default and one that accepts an existing instance of \u003ccode\u003ePlanNode.Types.ChildLink\u003c/code\u003e to use.\u003c/p\u003e\n"]]],[],null,[]]
