read

Use read to retrieve a row from a specified table by its key. You can optionally specify a subset of columns to return.

Basic syntax

To read an entire row from a table, use the following syntax:

(read table key)

To read specific columns from a row in a table, use the following syntax:

(read table key columns)

Arguments

Use the following arguments to specify the table, key, and optional columns when using the read Pact function.

Argument	Type	Description
table	table: <{row}>	Specifies the table from which to read the row. In the table schema, a row represents the structure of each row in the table.
key	string	Specifies the key of the row to read from the table.
columns	[string]	Specifies one or more column names to return from the row. If not provided, the entire row is returned (optional).

Return value

The read function returns an object representing the requested row or columns from the specified table.

• If you don't specify one or more columns as parameters, the function returns an object with the structure of the entire row.
• If you specify one or more columns as parameters, the function returns an object containing only the specified columns from the row.

Examples

he following example demonstrates defining a table schema for an accounts table that stores information about bank accounts, including the balance, currency, and owner of each account:

(defschema account
  balance:decimal
  currency:string
  owner:string)

(deftable accounts:{account})

You can then use the read function to read a row from the accounts table by its key id and retrieve only the balance and currency columns:

(read accounts id ['balance 'currency])