Function generatePostgresSchemaChange

src/drivers/postgres/generate-schema.ts:163–250

(
  driver: BaseDriver,
  change: DatabaseTableSchemaChange
)

//https://www.postgresql.org/docs/current/sql-createtable.html
export function generatePostgresSchemaChange(
  driver: BaseDriver,
  change: DatabaseTableSchemaChange
): string[] {
  const isCreateScript = !change.name.old;

  const lines = [];

  for (const col of change.columns) {
    if (col.new === null) lines.push(`DROP COLUMN ${col.old?.name}`);
    else if (col.old === null) {
      if (isCreateScript) {
        lines.push(generateCreateColumn(driver, col.new));
      } else {
        lines.push("ADD " + generateCreateColumn(driver, col.new));
      }
    } else {
      // check if there is rename
      if (col.new.name !== col.old.name) {
        lines.push(
          `RENAME COLUMN ${driver.escapeId(col.old.name)} TO ${driver.escapeId(
            col.new.name
          )}`
        );
      }

      // check if there is any changed except name
      if (!isEqual(omit(col.old, ["name"]), omit(col.new, ["name"]))) {
        lines.push(
          `ALTER COLUMN ${generateCreateColumn(
            driver,
            {
              name: col.new.name,
              type: col.new.type,
              pk: col.new.pk,
              constraint: {},
            },
            true
          )}`
        );
        if (col.new.constraint) {
          for (const s of generateConstraintModifyScript(
            driver,
            {
              ...col.new.constraint,
              primaryColumns: [col.new.name],
              uniqueColumns: [col.new.name],
              foreignKey: {
                ...col.new.constraint.foreignKey,
                columns: [col.new.name],
              },
            },
            change.name.old ?? ""
          )) {
            lines.push(s);
          }
        }
      }