KgBase

To load Apache TinkerPop Gremlin data using the CSV format, you must specify the vertices and the edges in separate files.

The loader can load from multiple vertex files and multiple edge files in a single load job.

For each load command, the set of files to be loaded must be in the same folder in the Amazon S3 bucket, and you specify the folder name for the source parameter. The file names and file name extensions are not important.

The Amazon Neptune CSV format follows the RFC 4180 CSV specification. For more information, see Common Format and MIME Type for CSV Files on the Internet Engineering Task Force (IETF) website.

Each file has a comma-separated header row. The header row consists of both system column headers and property column headers.

System Column Headers

The required and allowed system column headers are different for vertex files and edge files.

Each system column can appear only once in a header.

All labels are case sensitive.

Vertex headers

• ~id - Required - An ID for the Vertex
• ~label - A label for the vertex. Multiple label values are allowed. Separate values with a semicolon (;) character.

Edge headers

• ~id - Required - An ID for the edge.
• ~from - Required - The vertex ID of the from vertex.
• ~to - Required - The vertex ID of the to vertex.
• ~label - A label for the edge. Edges can only have a single label.

Property Column Headers

You can specify a column for a property by using the following syntax. The type names are not case sensitive.

propertyname:type

You can specify a column for an array type by adding [] to the type:

propertyname:type[]

The following example shows the column header for a property named age of type Int.

age:Int

Every row in the file would be required to have an integer in that position or be left empty.

Arrays of strings are allowed, but strings in an array must not include the semicolon (;) character.

Specifying the Cardinality of a Column

The column header can be used to specify cardinality for the property identified by the column. This allows the bulk loader to honor cardinality similarly to the way Gremlin queries do.

You specify the cardinality of a column like this:

propertyname:type(cardinality)

The cardinality value can be either single or set. The default is assumed to be set, meaning that the column can accept multiple values. In the case of edge files, cardinality is always single and specifying any other cardinality causes the loader to throw an exception.

If the cardinality is single, the loader throws an error if a previous value is already present when a value is loaded, or if multiple values are loaded. This behavior can be overridden so that an existing value is replaced when a new value is loaded by using the updateSingleCardinalityProperties flag. See Loader Command.

It is possible to use a cardinality setting with an array type, although this is not generally necessary. Here are the possible combinations:

• name:type – the cardinality is set, and the content is single-valued.
• name:type[] – the cardinality is set, and the content is multi-valued.
• name:type(single) – the cardinality is single, and the content is single-valued.
• name:type(set) – the cardinality is set, which is the same as the default, and the content is single-valued.
• name:type(set)[] – the cardinality is set, and the content is multi-valued.
• name:type(single)[] – this is contradictory and causes an error to be thrown.

The following section lists all the available Gremlin data types.

Gremlin Data Types

This is a list of the allowed property types, with a description of each type.

Bool (or Boolean)

Indicates a Boolean field. Allowed values: false, true

Whole Number Types

Values outside of the defined ranges result in an error.

Decimal Number Types

Supports both decimal notation or scientific notation. Also allows symbols such as (+/-) INFINITY or NaN. INF is not supported.

Float and double values that are too long are loaded and rounded to the nearest value for 24-bit (float) and 53-bit (double) precision. A midway value is rounded to 0 for the last remaining digit at the bit level.

String

Quotation marks are optional. Commas, newline, and carriage return characters are automatically escaped if they are included in a string surrounded by double quotation marks ("). Example: "Hello, World"

To include quotation marks in a quoted string, you can escape the quotation mark by using two in a row: Example: "Hello ""World"""

Arrays of strings are allowed, but strings in an array must not include the semicolon (;) character.

If you want to surround strings in an array with quotation marks, you must surround the whole array with one set of quotation marks. Example: "String one; String 2; String 3"

Date

Java date in ISO-8601 format. Supports the following formats: YYYY-MM-DD, YYYY-MM-DDTHH:mm, YYYY-MM-DDTHH:mm:SS, YYYY-MM-DDTHH:mm:SSZ

Gremlin Row Format

Delimiters

Fields in a row are separated by a comma. Records are separated by a newline or a newline followed by a carriage return.

Blank Fields

Blank fields are allowed for non-required columns (such as user-defined properties). A blank field still requires a comma separator. The example in the next section has a blank field in each example vertex.

Vertex IDs

~id values must be unique for all vertices in every vertex file. Multiple vertex rows with identical ~id values are applied to a single vertex in the graph.

Edge IDs

Additionally, ~id values must be unique for all edges in every edge file. Multiple edge rows with identical ~id values are applied to the single edge in the graph.

Labels

Labels are case sensitive.

String Values

Quotation marks are optional. Commas, newline, and carriage return characters are automatically escaped if they are included in a string surrounded by double quotation marks (").

CSV Format Specification

The Neptune CSV format follows the RFC 4180 CSV specification, including the following requirements.

• Both Unix and Windows style line endings are supported (\n or \r\n).
• Any field can be quoted (using double quotation marks).
• Fields containing a line-break, double-quote, or commas must be quoted. (If they are not, load aborts immediately.)
• A double quotation mark character (") in a field must be represented by two (double) quotation mark characters. For example, a string Hello "World" must be present as "Hello ""World""" in the data.
• Surrounding spaces between delimiters are ignored. If a row is present as value1, value2, they are stored as "value1" and "value2".
• Any other escape characters are stored verbatim. For example, "data1\tdata2" is stored as "data1\tdata2". No further escaping is needed as long as these characters are enclosed within quotation marks.
• Blank fields are allowed. A blank field is considered an empty value.
• Multiple values for a field are specified with a semicolon (;) between values.

For more information, see Common Format and MIME Type for CSV Files on the Internet Engineering Task Force (IETF) website.

Gremlin Example

The following diagram shows an example of two vertices and an edge taken from the TinkerPop Modern Graph.

The following is the graph in Neptune CSV load format.

Vertex file:

~id, name:String, age:Int, lang:String, ~label
v1, "marko", 29, , person
v2, "lop", , "java", software

Tabular view of the vertex file:

Edge file:

~id, ~from, ~to, ~label, weight:Double
e1, v1, v2, created, 0.4

Tabular view of the edge file:

Next Steps

Now that you know more about the loading formats, see Example: Loading Data into a Neptune DB Instance.