getOrCreateDataIndex

Retrieves an existing data index for a given table and specified key column(s), or creates the index if it does not already exist.

This method is part of the io.deephaven.engine.table.impl.indexer.DataIndexer class and is typically used via a static import.

Syntax

index = getOrCreateDataIndex(someTable, "KeyColumn1")
index = getOrCreateDataIndex(someTable, "KeyColumn1", "KeyColumn2")
index = getOrCreateDataIndex(someTable, ["KeyColumn1", "KeyColumn2"] as String[])

Parameters

Parameter	Type	Description
table	Table	The table from which to retrieve or create the data index.
keyColumnNames	String...	The name(s) of the key column(s) defining the index (varargs).
keyColumnNames	String[]	The name(s) of the key column(s) defining the index (array).

Returns

Returns the existing or newly created DataIndex object.

Examples

import static io.deephaven.engine.table.impl.indexer.DataIndexer.getOrCreateDataIndex
import static io.deephaven.engine.table.impl.indexer.DataIndexer.hasDataIndex

// Create a source table
def sourceTable = emptyTable(100).update(
    "Category = \"Cat\" + (int)(i % 4)",
    "ID = i"
)

// Check if an index exists on Category (it doesn't yet)
println "Has index on Category BEFORE: ${hasDataIndex(sourceTable, "Category")}"  // Output: false

// Get or create an index on Category
def indexCategory = getOrCreateDataIndex(sourceTable, "Category")
println "Index on Category: ${indexCategory}"  // Output: (DataIndex object)

// Check if an index exists on Category (it does now)
println "Has index on Category AFTER: ${hasDataIndex(sourceTable, "Category")}"  // Output: true

// Get or create an index on Category and ID
def indexCategoryId = getOrCreateDataIndex(sourceTable, "Category", "ID")
println "Index on Category, ID: ${indexCategory}"  // Output: (DataIndex object)
println "Has index on Category, ID: ${hasDataIndex(sourceTable, "Category", "ID")}" // Output: true

getOrCreateDataIndex

Syntax

Parameters

Returns

Examples

Related documentation