sequelize/sequelize · error · Error

${this._getDialect().name} does not support the BINARY optio

Error message

${this._getDialect().name} does not support the BINARY option for data types with a length greater than 4000.

What it means

Thrown by the IBMi STRING data-type override's toSql when the binary option is set and the declared length exceeds 4000. IBMi/Db2 maps STRING+binary to VARCHAR(n) FOR BIT DATA, which has a hard 4000-byte ceiling; longer binary strings must use BLOB.

Source

Thrown at packages/ibmi/src/_internal/data-types-overrides.ts:58

      }

      return `BLOB(${this.options.length})`;
    }

    return 'BLOB(1M)';
  }
}

export class STRING extends BaseTypes.STRING {
  toSql() {
    const length = this.options.length ?? 255;

    if (this.options.binary) {
      if (length <= 4000) {
        return `VARCHAR(${length}) FOR BIT DATA`;
      }

      throw new Error(
        `${this._getDialect().name} does not support the BINARY option for data types with a length greater than 4000.`,
      );
    }

    if (length <= 4000) {
      return `VARCHAR(${length})`;
    }

    return `CLOB(${length})`;
  }
}

export class CHAR extends BaseTypes.CHAR {
  toSql() {
    if (this.options.binary) {
      return `CHAR(${this.options.length ?? 255}) FOR BIT DATA`;
    }

View on GitHub (pinned to 7e1deec499)

Solutions

Reduce the length to <= 4000 for the binary string column.
Switch the column to DataTypes.BLOB for binary payloads larger than 4000 bytes.
Split the data or store a reference/identifier instead of a long binary blob.

Example fix

// before
DataTypes.STRING({ length: 8000, binary: true })
// after
DataTypes.BLOB

Defensive patterns

Strategy: validation

Validate before calling

if (attr.binary && typeof attr.length === 'number' && attr.length > 4000) {
  throw new Error('IBMi STRING binary length cannot exceed 4000; use BLOB');
}

Type guard

function isValidIbmiBinaryString(attr) {
  return !attr.binary || attr.length == null || attr.length <= 4000;
}

Prevention

Cap binary STRING length at 4000 on IBMi.
Use BLOB for larger binary payloads.
Review model definitions when porting from other dialects.

When it happens

Trigger: Defining a model attribute as DataTypes.STRING({ length: 8000, binary: true }) (or STRING.BINARY with length>4000) and triggering DDL generation (sync/autoMigrate).

Common situations: Porting a model from MySQL/Postgres with a long binary string column, or assuming STRING.BINARY scales to any length.

Related errors

AI-assisted analysis of sequelize/sequelize@7e1deec499 (2026-08-03). Data as JSON: /data/errors/f5fa4590ee330fc5.json. Report an issue: GitHub.