Import data wizard for Azure Cognitive Search

The Azure portal provides an Import data wizard on the Azure Cognitive Search dashboard for prototyping and loading an index. This article covers advantages and limitations of using the wizard, inputs and outputs, and some usage information. For hands-on guidance in stepping through the wizard using built-in sample data, see the Create an Azure Cognitive Search index using the Azure portal quickstart.

Operations that this wizard performs include:

1 - Connect to a supported Azure data source.

2 - Create an index schema, inferred by sampling source data.

3 - Optionally, add AI enrichments to extract or generate content and structure.

4 - Run the wizard to create objects, import data, set a schedule and other configuration options.

The wizard outputs a number of objects that are saved to your search service, which you can access programatically or in other tools.

Advantages and limitations

Before you write any code, you can use the wizard for prototyping and proof-of-concept testing. The wizard connects to external data sources, samples the data to create an initial index, and then imports the data as JSON documents into an index on Azure Cognitive Search.

Sampling is the process by which an index schema is inferred and it has some limitations. When the data source is created, the wizard picks a sample of documents to decide what columns are part of the data source. Not all files are read, as this could potentially take hours for very large data sources. Given a selection of documents, source metadata, such as field name or type, is used to create a fields collection in an index schema. Depending on the complexity of source data, you might need to edit the initial schema for accuracy, or extend it for completeness. You can make your changes inline on the index definition page.

Overall, the advantages of using the wizard are clear: as long as requirements are met, you can prototype a queryable index within minutes. Some of the complexities of indexing, such as providing data as JSON documents, are handled by the wizard.

Known limitations are summarized as follows:

  • The wizard does not support iteration or reuse. Each pass through the wizard creates a new index, skillset, and indexer configuration. Only data sources can be persisted and reused within the wizard. To edit or refine other objects, you have to use the REST APIs or .NET SDK to retrieve and modify the structures.

  • Source content must reside in a supported Azure data source, in a service under the same subscription.

  • Sampling is over a subset of source data. For large data sources, it's possible for the wizard to miss fields. You might need to extend the schema, or correct the inferred data types, if sampling is insufficient.

  • AI enrichment, as exposed in the portal, is limited to a few built-in skills.

  • A knowledge store, which can be created by the wizard, is limited to a few default projections. If you want to save enriched documents created by the wizard, the blob container and tables come with default names and structure.

Data source input

The Import data wizard connects to an external data source using the internal logic provided by Azure Cognitive Search indexers, which are equipped to sample the source, read metadata, crack documents to read content and structure, and serialize contents as JSON for subsequent import to Azure Cognitive Search.

You can only import from a single table, database view, or equivalent data structure, however the structure can include hierarchical or nested substructures. For more information, see How to model complex types.

You should create this single table or view before running the wizard, and it must contain content. For obvious reasons, it doesn't make sense to run the Import data wizard on an empty data source.

Selection Description
Existing data source If you already have indexers defined in your search service, you might have an existing data source definition that you can reuse. In Azure Cognitive Search, data source objects are only used by indexers. You can create a data source object programmatically or through the Import data wizard, and reuse them as needed.
Samples Azure Cognitive Search provides two built-in sample data sources that are used in tutorials and quickstarts: a real estate SQL database and a Hotels database hosted on Cosmos DB. For a walk through based on the Hotels sample, see the Create an index in the Azure portal quickstart.
Azure SQL Database Service name, credentials for a database user with read permission, and a database name can be specified either on the page or via an ADO.NET connection string. Choose the connection string option to view or customize properties.

The table or view that provides the rowset must be specified on the page. This option appears after the connection succeeds, giving a drop-down list so that you can make a selection.
SQL Server on Azure VM Specify a fully qualified service name, user ID and password, and database as a connection string. To use this data source, you must have previously installed a certificate in the local store that encrypts the connection. For instructions, see SQL VM connection to Azure Cognitive Search.

The table or view that provides the rowset must be specified on the page. This option appears after the connection succeeds, giving a drop-down list so that you can make a selection.
Azure Cosmos DB Requirements include the account, database, and collection. All documents in the collection will be included in the index. You can define a query to flatten or filter the rowset, or leave the query blank. A query is not required in this wizard.
Azure Blob Storage Requirements include the storage account and a container. Optionally, if blob names follow a virtual naming convention for grouping purposes, you can specify the virtual directory portion of the name as a folder under container. See Indexing Blob Storage for more information.
Azure Table Storage Requirements include the storage account and a table name. Optionally, you can specify a query to retrieve a subset of the tables. See Indexing Table Storage for more information.

Wizard output

Behind the scenes, the wizard creates, configures, and invokes the following objects. After the wizard runs, you can find its output in the portal pages. The Overview page of your service has lists of indexes, indexers, data sources, and skillsets. Index definitions can be viewed in full JSON in the portal. For other definitions, you can use the REST API to GET specific objects.

Object Description
Data Source Persists connection information to source data, including credentials. A data source object is used exclusively with indexers.
Index Physical data structure used for full text search and other queries.
Skillset A complete set of instructions for manipulating, transforming, and shaping content, including analyzing and extracting information from image files. Except for very simple and limited structures, it includes a reference to a Cognitive Services resource that provides enrichment. Optionally, it might also contain a knowledge store definition.
Indexer A configuration object specifying a data source, target index, an optional skillset, optional schedule, and optional configuration settings for error handing and base-64 encoding.

How to start the wizard

The Import data wizard is started from the command bar on the service Overview page.

  1. In the Azure portal, open the search service page from the dashboard or find your service in the service list.

  2. In the service overview page at the top, click Import data.

    Import data command in portal

You can also launch Import data from other Azure services, including Azure Cosmos DB, Azure SQL Database, and Azure Blob storage. Look for Add Azure Cognitive Search in the left-navigation pane on the service overview page.

How to edit or finish an index schema in the wizard

The wizard generates an incomplete index, which will be populated with documents obtained from the input data source. For a functional index, make sure you have the following elements defined.

  1. Is the field list complete? Add new fields that sampling missed, and remove any that don't add value to a search experience or that won't be used in a filter expression or scoring profile.

  2. Is the data type appropriate for the incoming data? Azure Cognitive Search supports the entity data model (EDM) data types. For Azure SQL data, there is mapping chart that lays out equivalent values. For more background, see Field mappings and transformations.

  3. Do you have one field that can serve as the key? This field must be Edm.string and it must uniquely identify a document. For relational data, it might be mapped to a primary key. For blobs, it might be the metadata-storage-path. If field values include spaces or dashes, you must set the Base-64 Encode Key option in the Create an Indexer step, under Advanced options, to suppress the validation check for these characters.

  4. Set attributes to determine how that field is used in an index.

    Take your time with this step because attributes determine the physical expression of fields in the index. If you want to change attributes later, even programmatically, you will almost always need to drop and rebuild the index. Core attributes like Searchable and Retrievable have a negligible impact on storage. Enabling filters and using suggesters increase storage requirements.

    • Searchable enables full-text search. Every field used in free form queries or in query expressions must have this attribute. Inverted indexes are created for each field that you mark as Searchable.

    • Retrievable returns the field in search results. Every field that provides content to search results must have this attribute. Setting this field does not appreciably effect index size.

    • Filterable allows the field to be referenced in filter expressions. Every field used in a $filter expression must have this attribute. Filter expressions are for exact matches. Because text strings remain intact, additional storage is required to accommodate the verbatim content.

    • Facetable enables the field for faceted navigation. Only fields also marked as Filterable can be marked as Facetable.

    • Sortable allows the field to be used in a sort. Every field used in an $Orderby expression must have this attribute.

  5. Do you need lexical analysis? For Edm.string fields that are Searchable, you can set an Analyzer if you want language-enhanced indexing and querying.

    The default is Standard Lucene but you could choose Microsoft English if you wanted to use Microsoft's analyzer for advanced lexical processing, such as resolving irregular noun and verb forms. Only language analyzers can be specified in the portal. Using a custom analyzer or a non-language analyzer like Keyword, Pattern, and so forth, must be done programmatically. For more information about analyzers, see Add language analyzers.

  6. Do you need typeahead functionality in the form of autocomplete or suggested results? Select the Suggester the checkbox to enable typeahead query suggestions and autocomplete on selected fields. Suggesters add to the number of tokenized terms in your index, and thus consume more storage.

Next steps

The best way to understand the benefits and limitations of the wizard is to step through it. The following quickstart guides you through each step.