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Data > Datasource Adapters

Flat File

AMI provides a large number of datasource adapters for different supported software. Alternatively, users may choose to attach flat files directly using this highly performant adapter.

Overview

The AMI Flat File Reader datasource adapter is a highly configurable adapter for processing extremely large files efficiently.

When creating datamodels using the flat files, AMI determines how to parse and store the data using a number of general directives.

Generally, the adapter can handle files containing data that have the following format:

  1. Delimited lists or ordered fields 

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    ticker,amount,purchase cost
GOOGL,100,158
AAPL,30,216
MSFT,20,430.1

  2. Key-value pairs 

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    ticker=GOOGL|amount=100|purchase cost=158
ticker=AAPL|amount=30|purchase cost=216
ticker=MSFT|amount=20|purchase cost=430.1

  3. Pattern matching 

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    Account 11232 has 1000 shares at $123.20 px
Account 12412 has 8900 shares at $430.90 px

Alternatively you can display the entire raw contents of a file in a single-column AMI table with the heading 'line.'

When creating a datamodel, AMI will default to auto-generating a raw table if it cannot automatically detect any mappings, or the user does not supply them.

Using the Adapter

Navigate to the AMI Data Modeler (Dashboard -> Data Modeler) and select "Attach Datasource."

Under the "Configuration" menu, fill in the following details:

  1. Name

    • Supply a user-defined name, e.g "RawFiles."

  2. URL

    • The full path to the directory containing your files.

Then click the "Add Datasource" button. The flat file datasource will now be available and visible in the Data Modeler:

Note

Files can also be accessed remotely via AMI Relay on machines where a relay has been installed.

When configuring the flat file reader, click the "Relay To Run on" dropdown menu and select the corresponding relay.

General Directives

These are the main directives that are used to parse raw files when creating a datamodel from the adapter:

See the section below for syntax to configure each directive.

By default, AMI will attempt to create a single-column table with the raw data if it cannot automatically parse the data.

In the datamodel creation wizard, it looks like this:

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{
  CREATE TABLE test_txt AS USE _file="/file.txt" 
  _delim="\n" 
  _quote="\"" 
  _escape="\\" 
  _skipLines="0" 
  _fields="String line" 
  _binary=false  
  EXECUTE SELECT * FROM file WHERE ${WHERE};
}

_file

Example: _file="path/to/file.type"

  • The file to read including file type.

_fields

Syntax: _fields="col1_type col1, col2_type col2, ..."

  • Type and name of the columns to be stored as a table in AMI. Allowed types are:

    • String
    • Long
    • Integer
    • Double
    • Float
    • Boolean
    • UTC

  • If column type is not supplied, defaults to String.

Note

Line numbers are added automatically by AMI via the _linenum directive. If the line number column is not supplied, it will default to type integer and be added to the end of the table schema.

Columns defined in the _pattern but not defined in _fields will be added to the end of the table schema.

_delim

Syntax: _delim="delimiter"

  • String used by AMI to separate each field.
  • Special characters like tabs and line breaks can be supplied as the following:
    • "\t"
    • "\n"

_conflateDelim

Syntax: _conflateDelim=true_or_false

  • If true, then one or more consecutive delimiters is treated as a single delimiter.

_quote

Syntax: _quote="quote_character"

  • Optional character denoting a quote in the supplied file.
  • If AMI encounters fields enclosed in the quotes, they will be parsed without in the final table.

_equals

Syntax: _equals="equals_char"

  • Supplied equality symbol for key-value pair mapping.

_escape

Syntax: _escape="escape_char"

  • Supplied escape character.

_mappings

Syntax: _mappings=from1=to1,from2=to2,...

  • Optional mappings directive for key-value pair files.
  • Used for key names that are not valid field names.
  • Used if multiple key names should be attributed to the same column heading.
  • For multiple column-to-pattern mappings, use \n (new line) to separate each one.

_binary

Syntax _binary=true/false

  • Indicates whether the file contains binary data.

_pattern

Syntax: _pattern=col1_type col1_name, ...=regex_describing_columns , _pattern=col1_name, ...=regex_describing_columns (if column typing is specified in _fields)

  • Used for files with data that aren't stored in a conventional format.
  • Uses regex for pattern matching.

Optional Line Directives

_skipLines

Syntax: _skipLines=number_of_lines

  • Number of lines to skip from the top of the file, for example if there is a header.
  • Default is 0.

_linenum

Syntax: _linenum=column_name

  • Name of the column that will contain the line number starting from 1.
  • If not supplied, default name is "linenum."
  • Starting number is inclusive of _skipLines, i.e starts from _skipLines+1

_filterOut

Syntax: _filterOut=regex

  • Any line that matches the supplied regular expression will be ignored.
  • Applied before parsing, so more performant than using the WHERE clause.

Examples:

  • _filterOut="Test": ignore any lines containing the text "Test."
  • _filterOut="^Comment": ignore any lines starting with "Comment."
  • _filterOut="This|That": ignore any lines containing the text "This" or "That."

_filterIn

Syntax: _filterIn=regex

  • Only lines that match the supplied regular expression will be considered.
  • Applied before parsing, so more performant than using the WHERE clause.

Examples:

  • _filterIn="3forge": ignore any lines that don't contain the word "3forge."
  • _filterIn="^Outgoing": ignore any lines that don't start with "Outgoing."
  • _filterIn="Data(.*)": ignore any lines that don't start with "Data", and only process the text after.

Examples

Delimited List

Sample data: 

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11232-33|Smith|20
'1332|ABC'||30
Account\|112|Jones|18

Directives:

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_delim="|"
_fields="code,lname,int age"
_quote="\'"
_escape="\\"

AMI Table:

linenum (int) code (string) lname (string) age (int)
1 11232-33 Smith 20
2 1332|ABC 30
3 Account|112 Jones 18

Key-Value Pair

For key-value pairs, the equals character needs to be specified. Mappings can optionally be supplied which will allow for AMI to populate columns according to user-defined mappings.

Sample data: 

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code=11232-33|lname=Smith|age=20
code='1332|ABC'|age=30
20=Act\|112|21=J|22=18

Directives: 

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_delim="|"
_equals="="
_fields="code,lname,int age"
_mappings="20=code,21=lname,22=age"
_quote="\'"
_escape="\\"

AMI Table:

linenum (int) code (string) lname (string) age (int)
1 11232-33 Smith 20
2 1332|ABC 30
3 Act|112 J 18

Pattern Matching

With pattern matching, fields are not strictly required however how you specify column names and typing depends on the regex pattern you choose.

To define the types of your columns, it is preferred to do this via the _pattern definition than in the _fields directive otherwise you may encounter type mis-matching. For example:

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_fields="name,long id, int age"
_pattern="name,long id,int age=some_regex

is equivalent to omitting the _fields directive entirely as the column types are specified in the pattern.

Example 1

Sample data: 

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GOOGL selling 1000 shares at px 158
AAPL selling 30 shares at px 216
MSFT selling 20 shares at px 430.1

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_pattern="string ticker,long amount,double price=(.*) selling (.*) shares at px (.*)"

Generates the AMI Table:

linenum (int) ticker (string) amount (long) price (double)
1 GOOGL 1000 158.0
2 AAPL 30 216.0
3 MSFT 20 430.1

Example 2

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_pattern="fname,lname,int age=User (.*) (.*) is (.*) years old\n lname,fname,int weight=User (.*),(.*) weighs (.*) pounds"

This defines two patterns such that:

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User John Smith is 20 years old
User Boy,Bobby weighs 130 pounds

Maps to:

linenum (int) fname (string) lname (string) age (int) weight(int)
1 John Smith 20
2 Bobby Boy 130