Import data from CSV files

You can bulk import data to node and relationship tables from CSV files using the COPY FROM command. It is highly recommended to use COPY FROM if you are creating large databases. You can use COPY FROM to import data into an empty table or to append data to an existing table.

The CSV import configuration can be manually set by specifying the parameters inside ( ) at the end of the the COPY FROM clause. The following table shows the configuration parameters supported:

Parameter	Description	Default Value
HEADER	Whether the first line of the CSV file is the header. Can be true or false.	false
DELIM	Character that separates different columns in a lines.	,
QUOTE	Character to start a string quote.	"
ESCAPE	Character within string quotes to escape QUOTE and other characters, e.g., a line break. See the important note below about line breaks lines below.	\
LIST_BEGIN/LIST_END	For the list data type, the delimiters to specify list begin and list end characters	[, ]
PARALLEL	Read csv files in parallel or not	true

The example below specifies that the CSV delimiter is| and also that the header row exists.

COPY User FROM "user.csv" (HEADER=true, DELIM="|");

Guidelines

• Copy nodes before relationships: In order to copy a relationship table R from a csv file RFile, the nodes that appear in RFile need to already exist in the database (either imported in bulk or inserted through Cypher data manipulation commands).
• Wrap strings inside quotes: Kùzu will accept strings in string columns both with and without quotes, though it’s recommended to wrap strings in quotes to avoid any ambiguity with delimiters.
• Avoid leading and trailing spaces: As per the CSV standard, Kùzu does not ignore leading and trailing spaces (e.g., if you input 213 for an integer value, that will be read as malformed integer and the corresponding node/rel property will be set to NULL.

Import to node table

Create a node table User as follows:

CREATE NODE TABLE User(name STRING, age INT64, reg_date DATE, PRIMARY KEY (name))

The CSV file user.csv contains the following fields:

name,age,reg_date
Adam,30,2020-06-22
Karissa,40,2019-05-12
...

The following statement will load user.csv into User table.

COPY User FROM "user.csv" (header=true);

Import to relationship table

When loading into a relationship table, Kùzu assumes the first two columns in the file are:

• FROM Node Column: The primary key of the FROM nodes.
• TO Node Column: The primary key of the TO nodes.

The rest of the columns correspond to relationship properties.

Create a relationship table Follows using the following Cypher query:

CREATE REL TABLE Follows(FROM User TO User, since DATE)

This reads data from the below CSV file follows.csv:

Adam,Karissa,2010-01-30
Karissa,Michelle,2014-01-30
...

The following statement loads the follows.csv file into a Follows table.

COPY Follows FROM "follows.csv";

Note that the header wasn’t present in the CSV file, hence the header parameter is not set.

Import multiple files to a single table

It is common practice to divide a large CSV file into several smaller files for cleaner data management. Kùzu can read multiple files with the same structure, consolidating their data into a single node or relationship table. You can specify that multiple files are loaded in the following ways:

Glob pattern

This is similar to the Unix glob pattern, where you specify file paths that match a given pattern. The following wildcard characters are supported:

Wildcard	Description
*	match any number of any characters (including none)
?	match any single character
[abc]	match any one of the characters enclosed within the brackets
[a-z]	match any one of the characters within the range

COPY User FROM "User*.csv"

List of files

Alternatively, you can just specify a list of files to be loaded.

COPY User FROM ["User0.csv", "User0.csv", "User2.csv"]