MSSQL throws the error: "The column 'column' was specified multiple times for 'table'." when using `field` property in model definition

What you are doing?

I am using MSSQL and I am trying to perform a .findAll with limit and offset with a model that has two associations (one hasMany and one belongsTo), I am trying to include the hasMany associations.

My model definition uses the fields property to map column names. Above is the full code to reproduce the issue

const Sequelize = require('sequelize')
const DataTypes = Sequelize.DataTypes

const sequelize = new Sequelize(process.env.CONNECTION_STRING, {
  timezone: 'America/Sao_Paulo',
  logging: console.log,
  dialect: 'mssql',
  dialectOptions: {
    encrypt: true
  },
  define: {
    charset: 'utf8',
    collation: 'utf8_general_ci'
  }
})

const ProcessoPessoa = sequelize.define('ProcessoPessoa', {
  id: {
    type: DataTypes.INTEGER,
    allowNull: false,
    primaryKey: true,
    field: 'Id'
  },

  processoId: {
    type: DataTypes.STRING,
    allowNull: false,
    field: 'ProcessoId'
  }
}, {
  freezeTableName: true,
  tableName: 'ProcessosPessoas',
  createdAt: false,
  updatedAt: false
})

const Superintendencia = sequelize.define('Superintendencia', {
  id: {
    type: DataTypes.INTEGER,
    allowNull: false,
    primaryKey: true,
    field: 'Id'
  },

  estadoId: {
    type: DataTypes.INTEGER,
    allowNull: false,
    references: {
      model: 'Estados',
      key: 'Id'
    },
    field: 'EstadoId'
  },

  nome: {
    type: DataTypes.STRING,
    allowNull: false,
    field: 'Nome'
  }
}, {
  freezeTableName: true,
  tableName: 'Superintendencias',
  createdAt: false,
  updatedAt: false
})

const Processo = sequelize.define('Processo', {
  id: {
    type: DataTypes.STRING,
    allowNull: false,
    primaryKey: true,
    field: 'Id'
  },

  superintendenciaId: {
    type: DataTypes.INTEGER,
    allowNull: true,
    field: 'SuperintendenciaId'
  }
}, {
  freezeTableName: true,
  tableName: 'Processos',
  createdAt: false,
  updatedAt: false
})

Processo.hasMany(ProcessoPessoa, {
  as: 'pessoas',
  foreignKey: 'ProcessoId'
})

// If I comment the following 4 lines that define the belongsTo association
// the problem go away (but of course, I create another problem)
Processo.belongsTo(Superintendencia, {
  as: 'superintendencia',
  foreignKey: 'SuperintendenciaId'
})

const options = {
  offset: 100,
  limit: 50,
  include: [{
    model: ProcessoPessoa,
    as: 'pessoas',
    required: false
  }]
}

Processo.findAll(options).then(function (results) {
  // Will never get here - MSSQL will throw an error
  console.log(JSON.stringify(results, null, 4))
})

What do you expect to happen?

I expected that the query would work

What is actually happening?

MSSQL is throwing the following error: The column 'SuperintendenciaId' was specified multiple times for 'Processo'. due to duplicated columns in the select that is generated as follows:

Output:

SELECT 
  [Processo].*,
  [pessoas].[Id] AS [pessoas.id],
  [pessoas].[ProcessoId] AS [pessoas.processoId],
  [pessoas].[ProcessoId] AS [pessoas.ProcessoId] -- I think this is also not needed (though not part of the problem)
FROM (
  SELECT 
    [Processo].[Id] AS [id],
    [Processo].[SuperintendenciaId] AS [superintendenciaId],
    [Processo].[SuperintendenciaId] -- This line is not expected and should not be created
   FROM 
    [Processos] AS [Processo]
   ORDER BY 
    [Id]
   OFFSET 100 ROWS FETCH NEXT 50 ROWS ONLY
) AS [Processo]
LEFT OUTER JOIN 
  [ProcessosPessoas] AS [pessoas] ON 
    [Processo].[id] = [pessoas].[ProcessoId];

Note that when I remove the field property from my Models then it works great.

Dialect: mssql Database version: MSSQL 12.0.2000.8 Sequelize version: 3.25.0

[renatoargh]

Just noticed that I can do this ugly workaround to prevent the error:

const options = {
  offset: 100,
  limit: 50,
  attributes: {
    exclude: ['SuperintendenciaId'] // here
  },
  include: [{
    model: ProcessoPessoa,
    as: 'pessoas',
    required: false,
    attributes: {
      exclude: ['ProcessoId'] // here
    },
  }]
}

The problema with this workaround is that I would have to remember to add this excludes throughout the whole project 😕

[jongear]

@renatoargh so I actually figured this one out. For your foreign key relationship you must use the exact casing used in the relationship in sequelize NOT the casing used in the database.

Original Processo snippet

Processo.belongsTo(Superintendencia, {
  as: 'superintendencia',
  foreignKey: 'SuperintendenciaId'
})

should be

Processo.belongsTo(Superintendencia, {
  as: 'superintendencia',
  foreignKey: 'superintendenciaId'
})

Original Processo snippet

Processo.hasMany(ProcessoPessoa, {
  as: 'pessoas',
  foreignKey: 'ProcessoId'
})

should be

Processo.hasMany(ProcessoPessoa, {
  as: 'pessoas',
  foreignKey: 'processoId'
})