MarkLogic 12 EA 2 Product DocumentationAccessPlan.prototype.unnestLeftOuter
AccessPlan.prototype.unnestLeftOuter( inputColumn as String, valueColumn as String, [ordinalColumn as String?] ) as ModifyPlan
Summary
This function flattens an array value into multiple rows.Then performs a prototype.joinLeftOuter on the rest of the rows.
| Parameters | |
|---|---|
| inputColumn | The input column, which contains an array, to flatten into rows. This can be a string of the column name or an op.col. Use op.viewCol or op.schemaCol if you need to identify columns in the two views that have the same column name. |
| valueColumn | The output column which contains the flattened array values. This can be a string of the column name or an op.col. Use op.viewCol or op.schemaCol as needed. |
| ordinalColumn | The ordinalColumn is optional. If specified, an additional column will be added to the rows of flattened array values, starting from 1. This can be a string of the column name or an op.col. Use op.viewCol or op.schemaCol as needed. |
Usage Notes
unnestLeftOuter is a method of the following classes:
Example
const op = require('/MarkLogic/optic');
const rows =
[
{rowId: 1, desc: ['ball', 'box']},
{rowId: 2, desc: 'square'},
{rowId: 3, desc: null}
];
const outputCols = [
{"column":"rowId", "type":"integer"},
{"column":"desc", "type":"none", "nullable":true}
];
op.fromParam('rows', "", outputCols)
.unnestLeftOuter('desc','descUnnest','ordinality')
.orderBy(['rowId', 'ordinality'])
.result('object', {"rows":rows});
/* This returns
[{"rowId":1, "desc":["ball", "box"], "descUnnest":"ball", "ordinality":1},
{"rowId":1, "desc":["ball", "box"], "descUnnest":"box", "ordinality":2},
{"rowId":2, "desc":"square", "descUnnest":"square", "ordinality":1},
{"rowId":3, "desc":null, "descUnnest":null, "ordinality":null}]
*/
Example
// Insert a template
declareUpdate();
const tde = require("/MarkLogic/tde.xqy");
const template = xdmp.toJSON(
{
"template":{
"context":"office",
"rows":[
{
"schemaName":"unnestSchema",
"viewName":"unnestView",
"columns":[
{
"name":"department",
"scalarType":"string",
"val":"department",
"nullable":true,
"invalidValues":"ignore"
},
{
"name":"teamMembers",
"scalarType":"string",
"val":"teamMembers",
"nullable":true,
"invalidValues":"ignore"
}
]
}
]
}
}
);
tde.templateInsert('/optic/unnest/unnestTemplate.json', template)
//insert a document
declareUpdate();
let doc = {office:[
{department:"Engineering", teamMembers: 'Bob,Alice'},
{department:"Sales", teamMembers:'Robert,Cindy'},
{department:"Marketing", teamMembers:""},
{department:"CEO-Office", teamMembers:null}
]};
xdmp.documentInsert('/optic/unnest/doc1.json', doc)
//perform a unnestLeftOuter
const op = require('/MarkLogic/optic');
op.fromView("unnestSchema","unnestView")
.bind([
op.as('teamMemberSequence', op.fn.tokenize(op.col('teamMembers'),','))
])
.unnestLeftOuter('teamMemberSequence','teamMember', 'ordinality')
.orderBy(['department', 'ordinality'])
.result();
/* This returns
[{"unnestSchema.unnestView.department":"CEO-Office", "teamMemberSequence":null, "unnestSchema.unnestView.teamMembers":null, "teamMember":null, "ordinality":null},
{"unnestSchema.unnestView.department":"Engineering", "teamMemberSequence":["Bob", "Alice"], "unnestSchema.unnestView.teamMembers":"Bob,Alice", "teamMember":"Bob", "ordinality":1},
{"unnestSchema.unnestView.department":"Engineering", "teamMemberSequence":["Bob", "Alice"], "unnestSchema.unnestView.teamMembers":"Bob,Alice", "teamMember":"Alice", "ordinality":2},
{"unnestSchema.unnestView.department":"Marketing", "teamMemberSequence":null, "unnestSchema.unnestView.teamMembers":"", "teamMember":null, "ordinality":null},
{"unnestSchema.unnestView.department":"Sales", "teamMemberSequence":["Robert", "Cindy"], "unnestSchema.unnestView.teamMembers":"Robert,Cindy", "teamMember":"Robert", "ordinality":1},
{"unnestSchema.unnestView.department":"Sales", "teamMemberSequence":["Robert", "Cindy"], "unnestSchema.unnestView.teamMembers":"Robert,Cindy", "teamMember":"Cindy", "ordinality":2}]
*/
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