Adding a Connection to Apache CouchDB

1. In the application console, navigate to the Connections page.
2. At the Add Connections panel, select the icon for the connection you want to add.
3. If the Apache CouchDB icon is not available, click the Add More icon to download and install the Apache CouchDB connector from the CData site.

For required properties, see the Settings tab.

For connection properties that are not typically required, see the Advanced tab.

Connecting to Apache CouchDB

Set the Url connection property to the URL of your Apache CouchDB instance. For example: http://localhost:5984

If you want your users (or JWTs) to have access only to specific databases, configure the admin_only_all_dbs option in your Apache CouchDB instance to grant all users access to the "/_all_dbs" endpoint, which is required by the Sync App for listing tables.

Authenticating to Apache CouchDB

• Basic: Basic username/password authentication.
• JWT: Authentication with a JWT.
• None: Anonymous access for databases that are public.

Basic Authentication

Set the following to connect to data:

• AuthScheme: Basic.
• User The Apache CouchDB user account used to authenticate.
• Password The Apache CouchDB password associated with the authenticating user.

JWT Authentication

Set AuthScheme to JWT.

You can either automatically generate (and, if applicable, refresh) a JWT or manually generate one:

Automatic Token Generation

Required

• JWTSubject: The name of the user to assign to the JWT.
• JWTAlgorithm: The algorithm to use for the JWT signature.
• JWTKeyType: The encryption key's type.
• JWTKey: The encryption key used to sign the JWT generated by the Sync App.

Optional

• JWTIssuer: The issuer of the JWT.
• JWTExpiration: The duration for which the JWT remains valid, in seconds.
• JWTHeaders: A collection of extra headers to include in the JWT header.
• JWTClaims: A collection of extra claims to include in the JWT payload.
• CredentialsLocation: The filepath of the settings file containing the JWT. If a settings file does not exist in this location, the Sync App creates a new settings file when it retrieves a JWT.

Manual Token Generation

You can generate the tokens yourself manually and pass them to the Sync App by using the JWTToken connection property.

Generating the Key Pair

When using asymmetric algorithms to sign the tokens, you must generate a private/public key pair. For that, a cryptographic library like OpenSSL can be used. For example:

# generate private key
openssl genrsa --out private_rsa256.pem 2048

# extract public key
openssl rsa -in private_rsa256.pem -pubout > public_rsa256.pem

JWT Configurations

Refer to CouchDB JWT Authentication Documentation for the following.

The alg and sub are required claims and will always be validated by the Apache CouchDB instance. Other required claims can be configured in the server (see required_claims). In that case, you must use JWTHeaders and JWTClaims so that the Sync App can include those additional claims when generating the JWT.

You can use roles_claim_name or the roles_claim_path options to assign roles to the JWTs.

An example configuration of the server and corresponding sample connection string are shown below:

Example Server Configuration

[chttpd]
...
authentication_handlers = {chttpd_auth, jwt_authentication_handler}, {chttpd_auth, cookie_authentication_handler}, {chttpd_auth, default_authentication_handler}
admin_only_all_dbs = false
...

[jwt_auth]
...
required_claims = exp
roles_claim_path = my.nested._couchdb\.roles
rsa:rsa_256 = -----BEGIN PUBLIC KEY-----\nYOUR_PUBLIC_KEY\n-----END PUBLIC KEY-----\n
...

Example Connection String

Url=http://localhost:5984;
JWTSubject=JWT User 1;
JWTAlgorithm=RS256;
JWTKeyType=PEMKEY_FILE;
JWTKey=PATH_TO_FOLDER\private_rsa256.pem;
JWTHeaders=kid : rsa_256 | Custom Header 1 : Test 1;
JWTClaims= my : eyJuZXN0ZWQiOnsiX2NvdWNoZGIucm9sZXMiOlsidXNlcjIiXX19 | Custom Claim 1 : Test 1;

Anonymous Authentication

Set the following to connect to data:

• AuthScheme: None.
• PublicDatabases: A comma-separated list of public databases to list as tables.

Inferring the Data Type

You can use the following properties to configure automatic data type detection, which is enabled by default.

• TypeDetectionScheme: You can use this property to enable or disable automatic type detection based on the value specified in RowScanDepth.
• RowScanDepth: This property determines the number of rows that will be scanned to determine column data types.

Apache CouchDB is a schema-less document database that provides high performance, availability, and scalability. These features are not necessarily incompatible with a standards-compliant query language like SQL-92. The following sections show various schemes that the Sync App offers to bridge the gap with relational SQL and a document database.

Automatic Schema Discovery

Parsing Nested Data

The Sync App models the schemaless Apache CouchDB objects into relational tables and translates SQL queries into Apache CouchDB queries to get the requested data.

Free-Form Queries

The schema of the table is necessary to report metadata, but you can write Free-Form Queries not tied to the schema to select, insert, update, or delete data from columns that do not exist in the schema (without flattening).

Vertical Flattening

See Vertical Flattening to process JSON arrays as separate tables.

JSON Functions

Query Mapping

See Query Mapping for more details on how various Apache CouchDB operations are represented as SQL.

Dynamic Views

The Sync App automatically infers a relational schema by inspecting a series of Apache CouchDB documents in a collection. You can use the RowScanDepth property to define the number of documents the Sync App will scan to do so. The columns identified during the discovery process depend on the FlattenArrays and FlattenObjects properties.

Flattening Objects

If FlattenObjects is set, all nested objects will be flattened into a series of columns. For example, consider the following document:

{
  id: 12,
  name: "Lohia Manufacturers Inc.",
  address: {street: "Main Street", city: "Chapel Hill", state: "NC"},
  offices: ["Chapel Hill", "London", "New York"],
  annual_revenue: 35,600,000
}

If FlattenObjects is not set, then the address.street, address.city, and address.state columns will not be broken apart. The address column of type string will instead represent the entire object. Its value would be {street: "Main Street", city: "Chapel Hill", state: "NC"}. See JSON Functions for more details on working with JSON aggregates.

You can change the separator character in the column name from a dot by setting SeparatorCharacter.

Flattening Arrays

The FlattenArrays property can be used to flatten array values into columns of their own. This is only recommended for arrays that are expected to be short, for example the coordinates below:

"coord": [ -73.856077, 40.848447 ]

It is best to leave other unbounded arrays as they are and piece out the data for them as needed using JSON Functions.

As discussed in Automatic Schema Discovery, intuited table schemas enable SQL access to unstructured Apache CouchDB data. JSON Functions enable you to use standard JSON functions to summarize Apache CouchDB data and extract values from any nested structures. However, you are not limited to these schemes.

After connecting you can query any nested structure without flattening the data. Any relations that you can access with FlattenArrays and FlattenObjects can also be accessed with an ad hoc SQL query.

Let's consider an example document from the following Restaurant data set:

 
{
  "address": {
    "building": "1007",
    "coord": [
      -73.856077,
      40.848447
    ],
    "street": "Morris Park Ave",
    "zipcode": "10462"
  },
  "borough": "Bronx",
  "cuisine": "Bakery",
  "grades": [
    {
      "grade": "A",
      "score": 2,
      "date": {
        "$date": "1393804800000"
      }
    },
    {
      "date": {
        "$date": "1378857600000"
      },
      "grade": "B",
      "score": 6
    },
    {
      "score": 10,
      "date": {
        "$date": "1358985600000"
      },
      "grade": "C"
    }
  ],
  "name": "Morris Park Bake Shop",
  "restaurant_id": "30075445"
} 

SELECT [address.building], [grades.1.grade] FROM restaurants WHERE restaurant_id = '30075445'

It is possible to retrieve an array of documents as if it were a separate table. Take the following JSON structure from the restaurants collection for example:

{
  "_id" : ObjectId("568c37b748ddf53c5ed98932"),
  "address" : {
    "building" : "1007",
    "coord" : [-73.856077, 40.848447],
    "street" : "Morris Park Ave",
    "zipcode" : "10462"
  },
  "borough" : "Bronx",
  "cuisine" : "Bakery",
  "grades" : [{
      "date" : ISODate("2014-03-03T00:00:00Z"),
      "grade" : "A",
      "score" : 2
    }, {
      "date" : ISODate("2013-09-11T00:00:00Z"),
      "grade" : "A",
      "score" : 6
    }, {
      "date" : ISODate("2013-01-24T00:00:00Z"),
      "grade" : "A",
      "score" : 10
    }, {
      "date" : ISODate("2011-11-23T00:00:00Z"),
      "grade" : "A",
      "score" : 9
    }, {
      "date" : ISODate("2011-03-10T00:00:00Z"),
      "grade" : "B",
      "score" : 14
    }],
  "name" : "Morris Park Bake Shop",
  "restaurant_id" : "30075445"
}

SELECT * FROM [restaurants.grades]

You may also want to include information from the base restaurants table. You can do this with a join. Flattened arrays can only be joined with the root document. The Sync App expects the left part of the join is the array document you want to flatten vertically. Disable SupportEnhancedSQL to join nested Apache CouchDB documents -- this type of query is supported through the Apache CouchDB API.

SELECT [restaurants].[restaurant_id], [restaurants.grades].* FROM [restaurants.grades] JOIN [restaurants] WHERE [restaurants].name = 'Morris Park Bake Shop'

The Sync App can return JSON structures as column values. The Sync App enables you to use standard SQL functions to work with these JSON structures. The examples in this section use the following array:

[
     { "grade": "A", "score": 2 },
     { "grade": "A", "score": 6 },
     { "grade": "A", "score": 10 },
     { "grade": "A", "score": 9 },
     { "grade": "B", "score": 14 }
]

JSON_EXTRACT

SELECT Name, JSON_EXTRACT(grades,'[0].grade') AS Grade, JSON_EXTRACT(grades,'[0].score') AS Score FROM Students;

JSON_COUNT

SELECT Name, JSON_COUNT(grades,'[x]') AS NumberOfGrades FROM Students;

JSON_SUM

SELECT Name, JSON_SUM(score,'[x].score') AS TotalScore FROM Students;

JSON_MIN

SELECT Name, JSON_MIN(score,'[x].score') AS LowestScore FROM Students;

JSON_MAX

SELECT Name, JSON_MAX(score,'[x].score') AS HighestScore FROM Students;

DOCUMENT

The DOCUMENT function can be used to retrieve the entire document as a JSON string. See the following query and its result as an example:

SELECT DOCUMENT(*) FROM Customers;

{ "id": 12, "name": "Lohia Manufacturers Inc.", "address": { "street": "Main Street", "city": "Chapel Hill", "state": "NC"}, "offices": [ "Chapel Hill", "London", "New York" ], "annual_revenue": 35,600,000 }

The Sync App maps SQL queries into the corresponding Apache CouchDB queries. The Sync App uses the Selector syntax to compute the desired results.

A detailed description of all the transformations is out of scope, but we will describe some of the common elements that are used.

SELECT Queries

The SELECT statement is mapped to the GET and POST methods. Below are example queries and the corresponding request payloads.

SELECT *
FROM sales

SELECT _id, value
FROM sales

{
  "fields": [
    "_id",
    "value"
  ],
  "skip": 0,
  "selector": {
    "_id": {
      "$exists": true
    }
  }
}

SELECT * 
FROM sales 
WHERE value=175033291697

{
  "selector": {
    "value": {
      "$eq": 175033291697
    }
  },
  "skip": 0
}

SELECT * 
FROM sales 
WHERE value = 175033291697 OR month='June'

{
  "selector": {
    "$or": [
      {
        "value": {
          "$eq": 175033291697
        }
      },
      {
        "month": {
          "$eq": "June"
        }
      }
    ]
  },
  "skip": 0
}

SELECT * 
FROM sales
WHERE name LIKE 'A%'

{
  "selector": {
    "name": {
      "$regex": "A%"
    }
  },
  "skip": 0
}

SELECT * FROM sales
WHERE month='June'
ORDER BY _id ASC

{
  "skip": 0,
  "sort": [
    {
      "_id": "asc"
    }
  ],
  "selector": {
    "month": {
      "$eq": "June"
    }
  }
}

SELECT *
FROM sales
WHERE month='June'
ORDER BY _id DESC

{
  "skip": 0,
  "sort": [
    {
      "_id": "desc"
    }
  ],
  "selector": {
    "month": {
      "$eq": "June"
    }
  }
}

INSERT Statements

The INSERT statement is mapped to the HTTP POST request, as shown in the following query and request payload.

SQL Query

INSERT INTO users (_id, age, status, [address.city], [address.postalcode]) 
VALUES ('bcd001', 45, 'A', 'Chapel Hill', 27517)

Apache CouchDB Query

{
  "address": {
    "city": "Chapel Hill",
    "postalcode": 27517
  },
  "_id": "bcd001",
  "age": 45,
  "status": "A"
}

UPDATE Statements

The UPDATE statement is mapped to the HTTP PUT method, as shown in the following query and request payload.

SQL Query

UPDATE users 
SET status = 'C', [address.postalcode] = 90210
WHERE _id = 'bcd001'

Apache CouchDB Query

{
  "_id": "bcd001",
  "_rev": "1-446f6c67e3a483feae8eaf112f18892c",
  "status": "C",
  "age": 45,
  "address": {
    "city": "Chapel Hill",
    "postalcode": 90210
  }
}

DELETE Statements

The DELETE statement is mapped to the DELETE method as shown below.

SQL Query

DELETE FROM users WHERE _id = 'bcd001'

Apache CouchDB Query

For this query, a DELETE request is sent to the users/{_id}?rev={_rev} endpoint.

The Sync App maps types from Apache CouchDB to the Sync App's own data types. The table below documents these mappings.

The data type that some columns are regarded as by the Sync App is dynamically assessed based on the values in the column. Possible type determinations are shown as comma-separated values below.

The number of rows checked when determining the data type of a column is controlled by the RowScanDepth connection property.

The connection string properties are the various options that can be used to establish a connection. This section provides a complete list of the options you can configure in the connection string for this provider. Click the links for further details.

Authentication

JWT Authentication

SSL

Firewall

Proxy

Logging

Schema

Miscellaneous

This section provides a complete list of the Authentication properties you can configure in the connection string for this provider.

The type of authentication to use when connecting to Apache CouchDB.

Remarks

• Basic: Set this to use basic User/Password authentication.
• JWT: JWT authentication.
• None: No authentication is used.

The URL used to connect to the Apache CouchDB.

Remarks

The URL used to connect to the Apache CouchDB in the format http://{server}:{port}.

Specifies the user ID of the authenticating Apache CouchDB user account.

Remarks

The authenticating server requires both User and Password to validate the user's identity.

Specifies the password of the authenticating user account.

Remarks

The authenticating server requires both User and Password to validate the user's identity.

Specify a comma-separated list of public databases to list as tables.

Remarks

This is needed for anonymous access (AuthScheme=None) because the database listing call requires user authentication.

This section provides a complete list of the JWT Authentication properties you can configure in the connection string for this provider.

The JWT to use for authentication.

Remarks

If you have manually generated a JWT, you can provide it in this connection property. If a value is not supplied in this connection property, the Sync App generates the token itself.

The user subject for which the application is requesting delegated access.

Remarks

This is used as the sub claim in the JWT.

Apache CouchDB uses this as the user’s name when validating the JWT.

The issuer of the JWT.

Remarks

If not specified, this connection property defaults to the name of the Sync App, including version information.

The encryption algorithm used for signing the JWT.

Remarks

This is used as the alg claim in the JWT. This property can take one of the following values:

The amount of time until the JWT expires, in seconds.

Remarks

This is used to calculate the exp claim in the JWT.

When set to -1, the Sync App generates the first token, but never refreshes it. This is the default value.

The type of the encryption key used for signing the JWT.

Remarks

This property can take one of the following values:

The encryption key for signing the JWT.

Remarks

The encryption key used for signing the JWT generated by the Sync App. The JWTKeyType field specifies the type of the key being used.

A collection of extra HTTP headers to include in the JWT header.

Remarks

The string should not contain any single quotes or double quotes.

The : character is a delimiter separating headers and their values, and the | character is a delimiter separating the header name-value pairs. End the list of headers with a semicolon. For example:

JWTHeaders = kid : key_1 | Custom Header 1 : value;

If you need to use more complex values such as JSON objects or arrays, they must be base64 encoded. For example:

JWTHeaders = kid : key_1 | my : eyJjdXN0b20iOlsianNvbiIsIm9iamVjdCJdfQ==;

By default, not all headers in the JWT are validated by Apache CouchDB (only alg). See the documentation of required_claims for information about enforcing the validation of additional headers.

A collection of extra claims to include in the JWT payload.

Remarks

The string should not contain any single quotes or double quotes.

The : character is a delimiter separating claims and their values, and the | character is a delimiter separating the name-value pairs of each claim. End the list of claims with a semicolon. For example:

JWTClaims = aud : https://my.couchdb.server | nbf : 1720444762;

If you need to use more complex values such as JSON objects or arrays, they have to be base64 encoded. For example:

JWTClaims = my : eyJuZXN0ZWQiOnsiX2NvdWNoZGIucm9sZXMiOlsidXNlcjIiXX19 | nbf : 1720444762;

By default, not all claims in the JWT are validated by Apache CouchDB (only alg). See the documentation of required_claims for information about enforcing the validation of additional claims.

The filepath of the settings file containing the JWT. If a settings file does not exist in this location, the provider creates a new settings file when it retrieves a JWT.

Remarks

If left unspecified, the default location is "<OS-dependent path prefix>\\CData\\ApacheCouchDB Data Provider\\CredentialsFile.txt", where <OS-dependent path prefix> is a different value depending on the operating system from which you are running the Sync App:

This section provides a complete list of the SSL properties you can configure in the connection string for this provider.

Specifies the certificate to be accepted from the server when connecting using TLS/SSL.

Remarks

If using a TLS/SSL connection, this property can be used to specify the TLS/SSL certificate to be accepted from the server. Any other certificate that is not trusted by the machine is rejected.

This property can take the following forms:

If not specified, any certificate trusted by the machine is accepted.

Use '*' to signify to accept all certificates. Note that this is not recommended due to security concerns.

This section provides a complete list of the Firewall properties you can configure in the connection string for this provider.

Specifies the protocol the provider uses to tunnel traffic through a proxy-based firewall.

Remarks

A proxy-based firewall (or proxy firewall) is a network security device that acts as an intermediary between user requests and the resources they access. The proxy accepts the request of an authenticated user, tunnels through the firewall, and transmits the request to the appropriate server.

Because the proxy evaluates and transfers data backets on behalf of the requesting users, the users never connect directly with the servers, only with the proxy.

Note: By default, the Sync App connects to the system proxy. To disable this behavior and connect to one of the following proxy types, set ProxyAutoDetect to false.

The following table provides port number information for each of the supported protocols.

To connect to HTTP proxies, use ProxyServer and ProxyPort. To authenticate to HTTP proxies, use ProxyAuthScheme, ProxyUser, and ProxyPassword.

Identifies the IP address, DNS name, or host name of a proxy used to traverse a firewall and relay user queries to network resources.

Remarks

A proxy-based firewall (or proxy firewall) is a network security device that acts as an intermediary between user requests and the resources they access. The proxy accepts the request of an authenticated user, tunnels through the firewall, and transmits the request to the appropriate server.

Because the proxy evaluates and transfers data backets on behalf of the requesting users, the users never connect directly with the servers, only with the proxy.

Specifies the TCP port to be used for a proxy-based firewall.

Remarks

A proxy-based firewall (or proxy firewall) is a network security device that acts as an intermediary between user requests and the resources they access. The proxy accepts the request of an authenticated user, tunnels through the firewall, and transmits the request to the appropriate server.

Because the proxy evaluates and transfers data backets on behalf of the requesting users, the users never connect directly with the servers, only with the proxy.

Identifies the user ID of the account authenticating to a proxy-based firewall.

Remarks

A proxy-based firewall (or proxy firewall) is a network security device that acts as an intermediary between user requests and the resources they access. The proxy accepts the request of an authenticated user, tunnels through the firewall, and transmits the request to the appropriate server.

Because the proxy evaluates and transfers data backets on behalf of the requesting users, the users never connect directly with the servers, only with the proxy.

Specifies the password of the user account authenticating to a proxy-based firewall.

Remarks

A proxy-based firewall (or proxy firewall) is a network security device that acts as an intermediary between user requests and the resources they access. The proxy accepts the request of an authenticated user, tunnels through the firewall, and transmits the request to the appropriate server.

Because the proxy evaluates and transfers data backets on behalf of the requesting users, the users never connect directly with the servers, only with the proxy.

This section provides a complete list of the Proxy properties you can configure in the connection string for this provider.

Specifies whether the provider checks your system proxy settings for existing proxy server configurations, rather than using a manually specified proxy server.

Remarks

When this connection property is set to True, the Sync App checks your system proxy settings for existing proxy server configurations (no need to manually supply proxy server details).

This connection property takes precedence over other proxy settings. Set to False if you want to manually configure the Sync App to connect to a specific proxy server.

To connect to an HTTP proxy, see ProxyServer. For other proxies, such as SOCKS or tunneling, see FirewallType.

The hostname or IP address of the proxy server that you want to route HTTP traffic through.

Remarks

The Sync App only routes HTTP traffic through the proxy server specified in this connection property when ProxyAutoDetect is set to False. If ProxyAutoDetect is set to True, which is the default, the Sync App instead routes HTTP traffic through the proxy server specified in your system proxy settings.

The TCP port on your specified proxy server (set in the ProxyServer connection property) that has been reserved for routing HTTP traffic to and from the client.

Remarks

The Sync App only routes HTTP traffic through the proxy server port specified in this connection property when ProxyAutoDetect is set to False. If ProxyAutoDetect is set to True, which is the default, the Sync App instead routes HTTP traffic through the proxy server port specified in your system proxy settings.

For other proxy types, see FirewallType.

Specifies the authentication method the provider uses when authenticating to the proxy server specified in the ProxyServer connection property.

Remarks

The authentication type can be one of the following:

• BASIC: The Sync App performs HTTP BASIC authentication.
• DIGEST: The Sync App performs HTTP DIGEST authentication.
• NTLM: The Sync App retrieves an NTLM token.
• NEGOTIATE: The Sync App retrieves an NTLM or Kerberos token based on the applicable protocol for authentication.
• NONE: Set this when the ProxyServer does not require authentication.

For all values other than "NONE", you must also set the ProxyUser and ProxyPassword connection properties.

If you need to use another authentication type, such as SOCKS 5 authentication, see FirewallType.

The username of a user account registered with the proxy server specified in the ProxyServer connection property.

Remarks

The ProxyUser and ProxyPassword connection properties are used to connect and authenticate against the HTTP proxy specified in ProxyServer.

After selecting one of the available authentication types in ProxyAuthScheme, set this property as follows:

The Sync App only uses this username if ProxyAutoDetect is set to False. If ProxyAutoDetect is set to True, which is the default, the Sync App instead uses the username specified in your system proxy settings.

The password associated with the user specified in the ProxyUser connection property.

Remarks

The ProxyUser and ProxyPassword connection properties are used to connect and authenticate against the HTTP proxy specified in ProxyServer.

After selecting one of the available authentication types in ProxyAuthScheme, set this property as follows:

For SOCKS 5 authentication or tunneling, see FirewallType.

The Sync App only uses this password if ProxyAutoDetect is set to False. If ProxyAutoDetect is set to True, which is the default, the Sync App instead uses the password specified in your system proxy settings.

The SSL type to use when connecting to the proxy server specified in the ProxyServer connection property.

Remarks

This property determines when to use SSL for the connection to the HTTP proxy specified by ProxyServer. You can set this connection property to the following values :

A semicolon separated list of destination hostnames or IPs that are exempt from connecting through the proxy server set in the ProxyServer connection property.

Remarks

The ProxyServer is used for all addresses, except for addresses defined in this property. Use semicolons to separate entries.

Note that the Sync App uses the system proxy settings by default, without further configuration needed. If you want to explicitly configure proxy exceptions for this connection, set ProxyAutoDetect to False.

This section provides a complete list of the Logging properties you can configure in the connection string for this provider.

Specifies the core modules to include in the log file. Use a semicolon-separated list of module names. By default, all modules are logged.

Remarks

This property lets you customize the log file content by specifying the logging modules to include. Logging modules categorize logged information into distinct areas, such as query execution, metadata, or SSL communication. Each module is represented by a four-character code, with some requiring a trailing space for three-letter names.

For example, EXEC logs query execution, and INFO logs general provider messages. To include multiple modules, separate their names with semicolons as follows: INFO;EXEC;SSL.

The Verbosity connection property takes precedence over the module-based filtering specified by this property. Only log entries that meet the verbosity level and belong to the specified modules are logged. Leave this property blank to include all available modules in the log file.

For a complete list of available modules and detailed guidance on configuring logging, refer to the Advanced Logging section in Logging.

This section provides a complete list of the Schema properties you can configure in the connection string for this provider.

Specifies the location of a directory containing schema files that define tables, views, and stored procedures. Depending on your service's requirements, this may be expressed as either an absolute path or a relative path.

Remarks

The Location property is only needed if you want to either customize definitions (for example, change a column name, ignore a column, etc.) or extend the data model with new tables, views, or stored procedures.

If left unspecified, the default location is %APPDATA%\\CData\\ApacheCouchDB Data Provider\\Schema, where %APPDATA% is set to the user's configuration directory:

Optional setting that restricts the schemas reported to a subset of all available schemas. For example, BrowsableSchemas=SchemaA,SchemaB,SchemaC .

Remarks

Listing all available database schemas can take extra time, thus degrading performance. Providing a list of schemas in the connection string saves time and improves performance.

Optional setting that restricts the tables reported to a subset of all available tables. For example, Tables=TableA,TableB,TableC .

Remarks

Listing all available tables from some databases can take extra time, thus degrading performance. Providing a list of tables in the connection string saves time and improves performance.

If there are lots of tables available and you already know which ones you want to work with, you can use this property to restrict your viewing to only those tables. To do this, specify the tables you want in a comma-separated list. Each table should be a valid SQL identifier with any special characters escaped using square brackets, double-quotes or backticks. For example, Tables=TableA,[TableB/WithSlash],WithCatalog.WithSchema.`TableC With Space`.

Note: If you are connecting to a data source with multiple schemas or catalogs, you must specify each table you want to view by its fully qualified name. This avoids ambiguity between tables that may exist in multiple catalogs or schemas.

Optional setting that restricts the views reported to a subset of the available tables. For example, Views=ViewA,ViewB,ViewC .

Remarks

Listing all available views from some databases can take extra time, thus degrading performance. Providing a list of views in the connection string saves time and improves performance.

If there are lots of views available and you already know which ones you want to work with, you can use this property to restrict your viewing to only those views. To do this, specify the views you want in a comma-separated list. Each view should be a valid SQL identifier with any special characters escaped using square brackets, double-quotes or backticks. For example, Views=ViewA,[ViewB/WithSlash],WithCatalog.WithSchema.`ViewC With Space`.

Note: If you are connecting to a data source with multiple schemas or catalogs, you must specify each view you want to examine by its fully qualified name. This avoids ambiguity between views that may exist in multiple catalogs or schemas.

Whether to list views from Apache CouchDB or not.

Remarks

Set this property to true for Apache CouchDB views to show up when listing tables.

This section provides a complete list of the Miscellaneous properties you can configure in the connection string for this provider.

Set FlattenArrays to the number of array elements to flatten into columns. Otherwise, arrays are returned as JSON strings.

Remarks

By default, nested arrays are returned as strings of JSON. The FlattenArrays property can be used to flatten the elements of nested arrays into columns of their own: Set FlattenArrays to the number of elements you want to return from nested arrays. The zero-based index is concatenated to the column name with a dot or the character specified by SeparatorCharacter. Other elements are ignored.

For example, you can return an arbitrary number of elements from an array of strings:

["FLOW-MATIC","LISP","COBOL"]

Setting FlattenArrays to -1 will flatten all the elements of nested arrays.

Using FlattenArrays is only recommended for arrays that are expected to be short. See NoSQL Database for other ways to access nested arrays.

Set FlattenObjects to true to flatten object properties into columns of their own. Otherwise, embedded objects as raw JSON strings.

Remarks

The property name is concatenated onto the object name with a dot or the character specified by SeparatorCharacter.

For example, you can flatten the nested objects below at connection time:

[
  { "grade": "A", "score": 2 },
  { "grade": "A", "score": 6 },
  { "grade": "A", "score": 10 },
  { "grade": "A", "score": 9 },
  { "grade": "B", "score": 14 }
]

Set FlexibleSchema to true to scan for additional metadata on the query result set. Otherwise, the metadata will remain the same.

Remarks

If false, the metadata will remain the same.

Specifies the maximum rows returned for queries without aggregation or GROUP BY.

Remarks

This property sets an upper limit on the number of rows the Sync App returns for queries that do not include aggregation or GROUP BY clauses. This limit ensures that queries do not return excessively large result sets by default.

When a query includes a LIMIT clause, the value specified in the query takes precedence over the MaxRows setting. If MaxRows is set to "-1", no row limit is enforced unless a LIMIT clause is explicitly included in the query.

This property is useful for optimizing performance and preventing excessive resource consumption when executing queries that could otherwise return very large datasets.

Specifies additional hidden properties for specific use cases. These are not required for typical provider functionality. Use a semicolon-separated list to define multiple properties.

Remarks

This property allows advanced users to configure hidden properties for specialized scenarios. These settings are not required for normal use cases but can address unique requirements or provide additional functionality. Multiple properties can be defined in a semicolon-separated list.

Note: It is strongly recommended to set these properties only when advised by the support team to address specific scenarios or issues.

Specify multiple properties in a semicolon-separated list.

Integration and Formatting

Specifies the maximum number of results to return from Apache CouchDB, per page. This setting overrides the default page size set by the datasource, which is optimized for most use cases.

Remarks

You may want to adjust the default pagesize to optimize results for a particular object or service endpoint you are querying. Be aware that increasing the page size may improve performance, but it could also result in higher memory consumption per page.

Specifies the pseudocolumns to expose as table columns. Use the format 'TableName=ColumnName;TableName=ColumnName'. The default is an empty string, which disables this property.

Remarks

This property allows you to define which pseudocolumns the Sync App exposes as table columns.

To specify individual pseudocolumns, use the following format: "Table1=Column1;Table1=Column2;Table2=Column3"

To include all pseudocolumns for all tables use: "*=*"

The maximum number of rows to scan to look for the columns available in a table.

Remarks

The columns in a table must be determined by scanning table rows. This value determines the maximum number of rows that will be scanned.

Setting a high value may decrease performance. Setting a low value may prevent the data type from being determined properly, especially when there is null data.

The character or characters used to denote hierarchy.

Remarks

In order to flatten out hierarchical structures, the Sync App needs some specifier that states the path to a column through the hierarchy. If this value is "." and a column comes back with the name address.city, this indicates that there is a mapped attribute with a child called city. If your data has columns that already use a single period within the attribute name, set the SeparatorCharacter to a different character or characters.

Specifies the maximum time, in seconds, that the provider waits for a server response before throwing a timeout error. The default is 60 seconds. Set to 0 to disable the timeout.

Remarks

This property controls the maximum time, in seconds, that the Sync App waits for an operation to complete before canceling it. If the timeout period expires before the operation finishes, the Sync App cancels the operation and throws an exception.

The timeout applies to each individual communication with the server rather than the entire query or operation. For example, a query could continue running beyond 60 seconds if each paging call completes within the timeout limit.

Setting this property to 0 disables the timeout, allowing operations to run indefinitely until they succeed or fail due to other conditions such as server-side timeouts, network interruptions, or resource limits on the server. Use this property cautiously to avoid long-running operations that could degrade performance or result in unresponsive behavior.

Determines how the provider will scan the data to determine the fields and data types in each document collection.

Remarks

Since Apache CouchDB is schema-less, the columns in a table must be determined by scanning table rows. Set TypeDetectionScheme to toggle the automatic discovery of data types. Set RowScanDepth to configure type detection.

See Also

Type detection is part of Automatic Schema Discovery. Set FlattenArrays and FlattenObjects to configure how the Sync App projects columns over the hierarchical data.

You can fine-tune the discovered columns and data types by calling CreateSchema to generate a schema file. Schema files have a simple format that makes it easy to change column behavior.

Specifies a filepath to a JSON configuration file defining custom views. The provider automatically detects and uses the views specified in this file.

Remarks

This property allows you to define and manage custom views through a JSON-formatted configuration file called UserDefinedViews.json. These views are automatically recognized by the Sync App and enable you to execute custom SQL queries as if they were standard database views. The JSON file defines each view as a root element with a child element called "query", which contains the SQL query for the view. For example:

{
	"MyView": {
		"query": "SELECT * FROM Movies WHERE MyColumn = 'value'"
	},
	"MyView2": {
		"query": "SELECT * FROM MyTable WHERE Id IN (1,2,3)"
	}
}

You can define multiple views in a single file and specify the filepath using this property. For example: UserDefinedViews=C:\Path\To\UserDefinedViews.json. When you use this property, only the specified views are seen by the Sync App.

Refer to User Defined Views for more information.