# Importing and managing data

The package provides three functions for importing and managing data with Neo4J.

### Importing data

The function neo4j_import() copies a .csv, .zip or .tar.gz file into the specified import directory on the Neo4J server. If the file is compressed, it will automatically decompress the file into the import directory and remove the compressed file afterwards.

neo4j_import() takes the following arguments:

• local should be a logical value indicating if the Neo4J server is locally or remotely hosted.
• con should be a list containing three elements: address, which should be address of the Neo4J hosting server, and uid and pwd as login credentials. The bolt address used for querying can be used only if the hosting server uses the same address. Only used if local = FALSE.
• source is the local path to the file to be imported. Use path.expand() if necessary.
• import_dir is the local or remote path to the Neo4J import directory. Use path.expand() if necessary.
• unzip_path is the path to the unzip executable on the local or remote server. Only used if a zip is imported.
• gunzip_path is the path to the gunzip executable on the local or remote server. Only used if a .tar.gz is imported.
• tar_path is the path to the tar executable on the local or remote server. Only used if a .tar.gz is imported.

Example, importing a file named data.csv to a locally hosted Neo4J server:

library(neo4jshell)

file  <- "data.csv" # assumes file is present in current working directory
impdir <- path.expand("~/neo4j-community-4.0.4/import")
neo4j_import(local = TRUE, source = file, import_dir = impdir)

The function returns either a success message or an error message.

### Removing files from the import directory

The function neo4j_rmfiles() allows the removal of files from the specified Neo4J import directory, which can be useful for cleaning up following import.

neo4j_rmfiles() takes the following arguments:

• local should be a logical value indicating if the Neo4J server is locally or remotely hosted.
• con should be a list containing three elements: address, which should be the address of the Neo4J hosting server, and uid and pwd as login credentials. The bolt address used for querying can be used only if the hosting server uses the same address. Only used if local = FALSE.
• source is a character vector listing the names of the files to be removed from the import directory.
• import_dir is the local or remote path to the Neo4J import directory. Use path.expand() if necessary.

Example, removing a file named data.csv from a locally hosted Neo4J server:

library(neo4jshell)

file  <- "data.csv"
impdir <- path.expand("~/neo4j-community-3.5.8/import")
neo4j_rmfiles(local = TRUE, files = file, import_dir = impdir)

The function returns either a success message or an error message.

### Removing subdirectories from the import directory

The function neo4j_rmdir() allows the removal of an entire sub-directory and all its contents from the specified Neo4J import directory, which can be useful for cleaning up following import.

neo4j_rmdir() takes the following arguments:

• local should be a logical value indicating if the Neo4J server is locally or remotely hosted.
• con should be a list containing three elements: address, which should be the address of the Neo4J hosting server, and uid and pwd as login credentials. The bolt address used for querying can be used only if the hosting server uses the same address. Only used if local = FALSE.
• dir is the name of the subdirectory of the import directory to be removed.
• import_dir is the local or remote path to the Neo4J import directory. Use path.expand() if necessary.

Example, removing a directory called data from a locally hosted Neo4J server:

library(neo4jshell)

impdir <- path.expand("~/neo4j-community-4.0.4/import")
neo4j_rmdir(local = TRUE, dir = datadir, import_dir = impdir)

The function returns either a success message or an error message.

### Smooth ETL in Neo4J

These functions can be used in combination with neo4j_query() to set up smooth ETL on a Neo4J server, by executing in the following order:

1. neo4j_import() to transfer a data file into the import directory or into a subdirectory (if the compressed file involves a subdirectory).
2. neo4j_query() to execute a load query referencing the imported file.
3. neo4j_rmfiles() or neo4j_rmdir() to remove the imported files following a successful load query.

### Note for Windows users

Paths to executable files that are provided as arguments to functions may need to be provided with appropriate extensions (eg cypher-shell.bat).