Version: 0.14.x

API Reference

The migrateDB method takes the three arguments, listed below.

  • config: Knex database configuration options.
  • schemaText: GraphQL schema text.
  • options:
    • dbSchemaName (default: 'public'): table schema: <schemaName>.<tableName>.
    • dbTablePrefix (default: ''): table name prefix: <prefix><tableName>.
    • dbColumnPrefix (default: ''): column name prefix: <prefix><columnName>.
    • updateComments (default: false): by default, migrateDB will not create or update comments on table and columns.
    • scalarMap (default: undefined): Custom Scalar mapping
    • mapListToJson (default: true): Map scalar/enum lists to json column type by default.
    • plugins (default: []): List of graphql-migrations plugins which describes queries that can be executed during migrations.
    • debug (default: false): displays debugging informations and SQL queries.
    • removeDirectivesFromSchema: (default: true): Strips all directives from schema before processing.
    • operationFilter: Filter out database operations that we don't want.

Table and Column Comments#

When updateComments is set to true it will automatically create/update table and column comments. Table / column comments are type or field description parsed from the model schema. The parsing logic takes care of stripping off all annotations leaving only business related comments.

The below model:

"""
Note business model table comment.
@model
"""
type Note {
id: ID!
"""
Note title.
"""
title: String!
}

Execution with the updateComments options set to true, as shown below

....
migrateDB(dbConfig, schemaText, {
updateComments: true
}).then((ops) => {
console.log(ops);
});
...

Will create / update the note table comments as shown below:

\d+
List of relations
Schema | Name | Type | Owner | Size | Description
--------+-------------+----------+------------+------------+------------------------------------
public | note | table | postgresql | 8192 bytes | Note business model table comment.
public | note_id_seq | sequence | postgresql | 8192 bytes |
(2 rows)
\d+ note
Table "public.note"
Column | Type | Modifiers | Storage | Stats target | Description
--------+------------------------+---------------------------------------------------+----------+--------------+-------------
title | character varying(255) | not null | extended | | Note title.
id | integer | not null default nextval('note_id_seq'::regclass) | plain | |
Indexes:
"note_pkey" PRIMARY KEY, btree (id)

NOTE: This options may not be supported by some database.

Scalar Mapping#

This option is a function used to specify custom Scalar mapping. It takes three arguments (field: GraphQLField, fieldType: GraphQLScalarType, dbAnnotation: any), depending on the field type you could return the TableColumnTypeDescriptor:

interface TableColumnTypeDescriptor {
/**
* Knex column builder function name.
*/
type: TableColumnType | string
/**
* Builder function arguments.
*/
args: any[]
}

For example, if you want a custom CustomDate scalar to be have a date type in the database:

import { migrateDB } from 'graphql-migrations';
const schemaText = ```
""" @model """
type Note {
id: ID!
title: String!
createdAt: CustomDate
}
scalar CustomDate
```;
const dbConfig = {
// Knex.js db configuration
};
migrateDB(dbConfig, schemaText, {
scalarMap: (
field: GraphQLField<any, any>,
scalarType: GraphQLScalarType,
annotations: any,
): TableColumnTypeDescriptor | null => {
// custom date converted to date type
if (scalarType.name === 'CustomDate') {
return {
type: 'date',
args: []
}
}
return undefined
}
}).then((ops) => {
console.log(ops);
});

A good example of this function is the default scalar type to database column function, that Graphback uses to convert scalar types based on certain creteria.

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