pg-to-dbml/src/funcs/transformFKsToRefsDBML.js

CLI tool to scan your postgres database, and output DBML.

const { EOL } = require('os');

module.exports = function transformFKsToRefsDBML(
  schemaName,
  constraints,
  includeSchemaName,
  columnGetter
) {
  // NOTE: only handling in-schema relationships... not FKs to other schemas
  //       because DBML does not yet handle that situation
  const dbml = constraints
    .filter(
      constraint =>
        constraint.constraintType === 'FOREIGN KEY' &&
        (includeSchemaName ? true : constraint.toSchema === schemaName)
    )
    .map(({ fromSchema, fromTable, fromColumns, toSchema, toTable, toColumns }) => {
      const cleanFromTable = fromTable.replace(/"/g, '');
      const cleanToTable = toTable.replace(/"/g, '');
      const foreignKey = columnGetter(fromSchema, cleanFromTable, fromColumns[0]);
      const foreignRelation = columnGetter(toSchema, cleanToTable, toColumns[0]);

      if (typeof foreignKey === 'undefined') {
        console.log('foreignKey is undefined!');
      }

      if (typeof foreignRelation === 'undefined') {
        console.log('foreignRelation is undefined!');
      }

      const fromString = includeSchemaName
        ? `${fromSchema}."${cleanFromTable}"`
        : `"${cleanFromTable}"`;
      const toString = includeSchemaName ? `"${toSchema}"."${cleanToTable}"` : `"${cleanToTable}"`;

      return `${EOL}Ref: ${fromString}.${foreignKey.column_name} > ${toString}.${foreignRelation.column_name}`;
    })
    .join(``);

  return `${dbml} ${EOL} ${EOL}`;
};