// Schema Interface
// -------

// The SchemaInterface are the publically accessible methods
// when creating or modifying an existing schema, Each of
// these methods are mixed into the `knex.schema` object,
// and pass-through to creating a `SchemaBuilder` instance,
// which is used as the context of the `this` value below.
var SchemaInterface = {

  // Modify a table on the schema.
  table: function(callback) {
    this.callback(callback);
    return this._setType('table');
  },

  // Create a new table on the schema.
  createTable: function(callback) {
    this._addCommand('createTable');
    this.callback(callback);
    return this._setType('createTable');
  },

  // Drop a table from the schema.
  dropTable: function() {
    this._addCommand('dropTable');
    return this._setType('dropTable');
  },

  // Drop a table from the schema if it exists.
  dropTableIfExists: function() {
    this._addCommand('dropTableIfExists');
    return this._setType('dropTableIfExists');
  },

  // Rename a table on the schema.
  renameTable: function(to) {
    this._addCommand('renameTable', {to: to});
    return this._setType('renameTable');
  },

  // Determine if the given table exists.
  hasTable: function() {
    this.bindings.push(this.table);
    this._addCommand('tableExists');
    return this._setType('tableExists');
  },

  // Determine if the column exists
  hasColumn: function(column) {
    this.bindings.push(this.table, column);
    this._addCommand('columnExists');
    return this._setType('columnExists');
  }

};

exports.SchemaInterface = SchemaInterface;