Budibase/budibase · error · Error

Cannot re-use the linked column name for a linked table.

Error message

Cannot re-use the linked column name for a linked table.

What it means

`validateTable` tracks each link schema entry by `tableId + fieldName` in the `usedAlready` array while the table is saved. If two link columns resolve to the same unique key — the same fieldName used twice in one table, or the same fieldName on link columns pointing at the same table — the save is rejected to keep link document storage unambiguous.

Source

Thrown at packages/server/src/db/linkedRows/LinkController.ts:110

  /**
   * Makes sure the passed in table schema contains valid relationship structures.
   */
  validateTable(table: Table) {
    const usedAlready = []
    for (let schema of Object.values(table.schema)) {
      if (schema.type !== FieldType.LINK) {
        continue
      }
      if (
        schema.fieldName &&
        !schema.autocolumn &&
        !schema.fieldName.match(ValidColumnNameRegex)
      ) {
        throw new Error("Column names can't contain special characters")
      }
      const unique = schema.tableId! + schema?.fieldName
      if (usedAlready.indexOf(unique) !== -1) {
        throw new Error(
          "Cannot re-use the linked column name for a linked table."
        )
      }
      usedAlready.push(unique)
    }
  }

  /**
   * Returns whether the two link schemas are equal (in the important parts, not a pure equality check)
   */
  areLinkSchemasEqual(linkSchema1: FieldSchema, linkSchema2: FieldSchema) {
    const compareFields = [
      "name",
      "type",
      "tableId",
      "fieldName",
      "autocolumn",
      "relationshipType",

View on GitHub (pinned to a81a902e9a)

Solutions

1. Rename one of the duplicate link columns so each fieldName is unique within the table.
2. Inspect table.schema via the API and remove redundant duplicate link entries before saving.
3. If the duplication comes from import code, deduplicate schema entries by fieldName before writing the table.

Example fix

// before
schema: { related_a: {type:"link", tableId: T}, related_a: {type:"link", tableId: T} }
// after
schema: { related_orders: {type:"link", tableId: T}, related_shipments: {type:"link", tableId: T} }

const seen = new Set<string>()
for (const [name, schema] of Object.entries(table.schema)) {
  if (schema.type !== "link") continue
  const key = schema.tableId + name
  if (seen.has(key)) throw new Error(`Duplicate link column '${name}' for table ${schema.tableId}`)
  seen.add(key)
}

try {
  await api.post(`/tables`, table)
} catch (err) {
  if (err.message.includes("re-use the linked column name")) {
    table.schema = dedupeLinkColumns(table.schema)
    return api.post(`/tables`, table)
  }
  throw err
}

When it happens

Trigger: Defining two link columns with identical fieldName in a single table; a copy/paste or import creating duplicate link schema entries; API calls that PATCH the table schema appending a link column whose fieldName already exists on the same target table.

Common situations: Duplicating a table definition and accidentally duplicating link fields; CSV/table import tooling merging schemas; automation or plugin code updating the schema without checking for existing link field names.

Related errors

• Column names can't contain special characters
• Relationship Error: Invalid value
• DB does not exist
• CouchDB error: ${err.message}
• Unable to retrieve row ${row._id} after saving.

AI-assisted analysis of Budibase/budibase@a81a902e9a (2026-08-29). Data as JSON: /api/errors/6dcecde255030029. Report an issue: GitHub.