Upload Local Csv File to Heroku Postgres

In this PostgreSQL tutorial, we will discuss how to import CSV file into PostgreSQL and we volition encompass different methods to import the CSV file into PostgreSQL. Below are the topics that nosotros volition encompass in this section:

• How to import csv file into postgresql database
• How to import csv file into postgresql database using python
• How to import csv file into postgresql database using java
• How to import csv file in postgresql using command line
• How to import csv file in postgresql using pgadmin

Before we begin, let's beginning sympathize the demand for importing CSV files into PostgreSQL. Here are some of the reasons.

1. Sometimes we don't want to write multiple insert statements to insert data into a table because of cumbersome and takes time.
2. Or peradventure data is available outside of the database in a file with a large number of records that yous tin can't insert one past one manually into the database.
3. Maybe you are a data engineer or information analyst and you have collected your information in a file. Using this file, you can't query well-nigh your question or whatever data y'all need. After importing these files into the database y'all volition be able to query or search for the insights that you need and perform some assay.

How to import csv file into postgre database

Let's brainstorm, beginning create a CSV file that stands for "comma-separated values" and it saves data in tabular format.

To create a CSV, open a notepad and type the given data to create a CSV file. And in the stop, salve the file where you desire in your arrangement's drive.

How to import CSV file into PostgreSQL

Here are some of the primary features of a CSV file.

• In the CSV file, each information is separated using commas. Information technology can as well be separated using characters like tab, semicolon, etc.
• In the to a higher place file, the data is separated using commas like id, name, class. Above is the elementary structure of the CSV file but it can comprise thousands of lines or long entries separated by semicolons.
• And some CSV file contains a header or some don't.
• If you remove entries like id, name, grade from the to a higher place file, then it will get a CSV file without a header, and here the header is id, proper noun, class.
• CSV files are designed in a way that tin exist imported and exported into whatsoever programs or can be opened using unproblematic text-editor, notepad, ms-excel etc.

Now you have enough information about the CSV file and how it is created. Let'southward move to import the CSV file into the Postgres database.

Note: Whether we are a Windows or Linux user, the aforementioned commands are used everywhere to import CSV files into the Postgres database.

Syntax:

          COPY [Table Name] FROM '[Absolute Path to File]' DELIMITER '[Delimiter Graphic symbol]' CSV [HEADER];        

Before importing data, you must have a tabular array in the database that can hold information. While importing a CSV file, check for the header if exists and and then mention the header in the query otherwise doesn't mention it. And also keep in mind the delimiter that is used in the file.

How to import CSV file into PostgreSQL

Now you know about the header and delimiter in the file, time to import them into the database.

So our file contains three columns 'id', 'name', 'class', and the datatype of id is an integer, the proper noun is varchar, and class is an integer.

The next step is to create a tabular array that tin can hold all of this information. For this, yous can also refer to "Create a table in PostgreSQL".

How to import CSV file into Postgresql

Before importing the CSV, we will look at the necessary parts of the query:

• Re-create: It is command for copying information from csv file to table

• Table Name: Name of the table 'pupil'
• Absolute Path: Information technology is location of the csv file on your system. In this example it is on the drive, so the path is: 'D:/student_details.csv'
• Delimiter Grapheme : which delimiter is used in csv file, here in this example is commas ' , '.
• HEADER: does csv file contains a header

Now we will import the created CSV file into the student tabular array in Postgresql using this query.

          COPY student FROM 'D:/student_details.csv' DELIMITER ',' CSV HEADER;        

How to import CSV file into Postgresql

Later on running the above query, verify the imported data using 'select * from student'. If data is imported successfully and then it volition bear witness the imported data in the output otherwise it volition evidence an empty table.

Let'south again import some of the CSV files into the database with different columns and data. The file data is given below that volition exist imported into the database.

major cities in notepad

The red colour box shows that the header of the file or we can call it columns of the tabular array.

Let's import the above file into the database named Postgres, for that first we will create the new empty table.

major city empty tabular array

The to a higher place code creates the four columns and the cavalcade name is id, Canada, Australia, New Zealand.

The below code will import the file into an empty tabular array named major_city.

          COPY major_city FROM 'C:/major_cities.csv' DELIMITER ',' CSV HEADER; SELECT * FROM major_city;                  

postgresql imported file code

Read: PostgreSQL Export Tabular array to CSV

How to import CSV file into Posgtresql database using python

To import CSV files from python into the Postgresql database, python has a library called psycopg2 that helps in communicating with the Postgresql database running on a server. What is "Psycopg2"?. Information technology is an open-source library that acts equally a Postgres protocol.

If the application needs to communicate with the Postgres server then we demand a kind of client that can speak database protocol with the Postgres server.

Before connecting to the Postgres server, please install the necessary library and follow the below command to install Psycopg2 from your terminal.

          pip install psycopg2        

How to import CSV file into Postgresql database using python

Now, open whatever IDE ( Integrated evolution environment ) similar PyCharm, Jupyter, visual studio, etc, and follow the following steps.

• Import psycopg2 into the environment using :

          import psycopg2 equally psg        

• Connect Postgres database using :

          conn = psycopg2.connect("host=localhost dbname=postgres user=postgres")        

Hither is the connecting to Postgres server that returns connection object which means a persistent session is created to communicate with a database.

Next, let'south empathize "What are the parameters in connect method of psycopg2?."

• host: It is the host where the Postgres database server is running, in our instance it is localhost.
• dbname: Name of the database that you want to connect
• user: Proper noun of the user for that database

Now you lot have a connection object (conn) merely you can't issue a command or query with the connection object. Instead, yous demand another object called the cursor object that will be created by calling Cursor() method on the connectedness object.

          cur = conn.cursor()        

How to import CSV file into Postgresql using python

To execute the database query for importing CSV files into the database, you need to open up your CSV file using with open( ) method of python and read each line from the file. Input to the copy_from( ) method of the cursor object that loads the file into a tabular array.

          import psycopg2 conn = psycopg2.connect("host=localhost dbname=student user=postgres password=12345") cur = conn.cursor() with open('D:/student_details.csv', 'r') as f:        next(f) #  To Skip the header row.     cur.copy_from(f, 'student', sep=',')  conn.commit()        

How to import CSV file into Postgresql using python

• with open('D:/student_details.csv', 'r') as f: this code helps in opening file and render file equally an object for the manipulation of the opened file. And in the finish, information technology closes the opened file.
• side by side(f): It is used to skip the header.
• cur.copy_from(f,' educatee',sep=','): Here you demand to know copy_from() that requires parameters or arguments.
• First argument is the file to load, the 2d name of the table where the file is loaded, and the delimiter that split data in the file.

Read: How to backup PostgreSQL database

How to import CSV file into Posgtresql database using java

In java, yous can import CSV files into the Postgresql database. For this implementation, we need to create three java files in your src and jar files in the lib folder of the java project:

How to import CSV file into PostgreSQL using java

                      CSVLoader.java            import java.io.FileNotFoundException; import coffee.io.FileReader; import java.sql.Connection; import java.sql.PreparedStatement; import java.util.Date;  import org.apache.eatables.lang.StringUtils;  import au.com.bytecode.opencsv.CSVReader;  public form CSVLoader {  	private static last  		Cord SQL_INSERT = "INSERT INTO ${table}(${keys}) VALUES(${values})"; 	private static last String TABLE_REGEX = "\\$\\{tabular array\\}"; 	individual static final Cord KEYS_REGEX = "\\$\\{keys\\}"; 	private static final String VALUES_REGEX = "\\$\\{values\\}";  	private Connection connectedness; 	individual char seprator;  	/** 	 * Public constructor to build CSVLoader object with 	 * Connectedness details. The connection is airtight on success 	 * or failure. 	 * @param connection 	 */ 	public CSVLoader(Connectedness connection) { 		this.connexion = connexion; 		//Set up default separator 		this.seprator = ','; 	} 	 	/** 	 * Parse CSV file using OpenCSV library and load in  	 * given database table.  	 * @param csvFile Input CSV file 	 * @param tableName Database table name to import data 	 * @param truncateBeforeLoad Truncate the table before inserting  	 * 			new records. 	 * @throws Exception 	 */ 	public void loadCSV(String csvFile, String tableName, 			boolean truncateBeforeLoad) throws Exception {  		CSVReader csvReader = null; 		if(aught == this.connection) { 			throw new Exception("Non a valid connexion."); 		} 		try { 			 			csvReader = new CSVReader(new FileReader(csvFile), this.seprator);  		} catch (Exception due east) { 			e.printStackTrace(); 			throw new Exception("Error occured while executing file. " 					+ e.getMessage()); 		}  		String[] headerRow = csvReader.readNext();  		if (naught == headerRow) { 			throw new FileNotFoundException( 					"No columns defined in given CSV file." + 					"Delight check the CSV file format."); 		}  		String questionmarks = StringUtils.repeat("?,", headerRow.length); 		questionmarks = (String) questionmarks.subSequence(0, questionmarks 				.length() - 1);  		String query = SQL_INSERT.replaceFirst(TABLE_REGEX, tableName); 		query = query 				.replaceFirst(KEYS_REGEX, StringUtils.join(headerRow, ",")); 		query = query.replaceFirst(VALUES_REGEX, questionmarks);  		System.out.println("Query: " + query);  		Cord[] nextLine; 		Connection con = null; 		PreparedStatement ps = null; 		try { 			con = this.connexion; 			con.setAutoCommit(false); 			ps = con.prepareStatement(query);  			if(truncateBeforeLoad) { 				//delete data from tabular array earlier loading csv 				con.createStatement().execute("DELETE FROM " + tableName); 			}  			last int batchSize = k; 			int count = 0; 			Date engagement = nil; 			while ((nextLine = csvReader.readNext()) != null) {  				if (null != nextLine) { 					int alphabetize = 1; 					for (Cord string : nextLine) { 						date = DateUtil.convertToDate(string); 						if (null != date) { 							ps.setDate(index++, new java.sql.Date(date 									.getTime())); 						} else { 							ps.setString(index++, string); 						} 					} 					ps.addBatch(); 				} 				if (++count % batchSize == 0) { 					ps.executeBatch(); 				} 			} 			ps.executeBatch(); // insert remaining records 			con.commit(); 		} catch (Exception e) { 			con.rollback(); 			east.printStackTrace(); 			throw new Exception( 					"Mistake occured while loading data from file to database." 							+ e.getMessage()); 		} finally { 			if (zero != ps) 				ps.shut(); 			if (null != con) 				con.close();  			csvReader.shut(); 		} 	}  	public char getSeprator() { 		return seprator; 	}  	public void setSeprator(char seprator) { 		this.seprator = seprator; 	}  }        

                      DateUtil.java            import coffee.text.ParseException; import java.text.SimpleDateFormat; import java.util.ArrayList; import coffee.util.Date; import coffee.util.List;   public class DateUtil {       // List of all date formats that we want to parse.     // Add your own format here.     individual static List<SimpleDateFormat>              dateFormats = new ArrayList<SimpleDateFormat>() { 		private static final long serialVersionUID = 1L;  		{             add(new SimpleDateFormat("Chiliad/dd/yyyy"));             add together(new SimpleDateFormat("dd.M.yyyy"));             add(new SimpleDateFormat("M/dd/yyyy hh:mm:ss a"));             add together(new SimpleDateFormat("dd.M.yyyy hh:mm:ss a"));             add together(new SimpleDateFormat("dd.MMM.yyyy"));             add(new SimpleDateFormat("dd-MMM-yyyy"));         }     };       /**      * Convert String with various formats into java.util.Date      *       * @param input      *            Date equally a string      * @return java.util.Date object if input cord is parsed       *          successfully else returns aught      */     public static Date convertToDate(String input) {         Appointment date = cipher;         if(zippo == input) {             return null;         }         for (SimpleDateFormat format : dateFormats) {             effort {             	format.setLenient(false);                 date = format.parse(input);             } catch (ParseException e) {                 //Shhh.. try other formats             }             if (date != aught) {                 break;             }         }           return appointment;     }      }        

                      PostgreSQLJDBC.coffee            import coffee.sql.Connection; import java.sql.DriverManager;      public form PostgreSQLJDBC {     public static void main(String[] args) { 		attempt {  			CSVLoader loader = new CSVLoader(getConnection()); 			loader.loadCSV("East:\\student_details.csv", "student", true); 			 		} catch (Exception eastward) { 			east.printStackTrace(); 		} 	}    private static Connection getConnection() {       Connection c = cypher;       endeavour {          Class.forName("org.postgresql.Commuter");          c = DriverManager             .getConnection("jdbc:postgresql://localhost:5432/postgres",             "postgres", "12345");             System.out.println("Opened database successfully");              } catch (Exception e) {          eastward.printStackTrace();          System.err.println(e.getClass().getName()+": "+e.getMessage());          Arrangement.go out(0);       }              return c;    } }        

You lot don't demand to know everything, focus on these lines in PostgreSQLJDBC.java.  And change the database name and user name in this file according to your demand.

          CSVLoader loader = new CSVLoader(getConnection()); loader.loadCSV("E:\\student_details.csv", "student", true);        

The above 2 lines assist in getting a connection to the database and load the CSV files into a tabular array.

• loadCSV( ) : method accepts a iii-parameter, the path of the CSV file, the tabular array where you lot want to load the CSV file, and do yous want to truncate the table or not.
• Run PostgreSQLJDBC.coffee file, your CSV file is loaded into the tabular array successfully.

Read: PostgreSQL drop all tables

How to import csv file into postgresql using control-line

To import CSV file into Postgresql using command-line, follow these steps:

1. Open command prompt by WIN + R keys, type cmd and press Enter.
2. Enter the given command to import csv file into pupil table of postgres database.

          psql -d dbname -U username -c "query to import csv file into tabular array"                            or  psql -d postgres -U postgres -c "\re-create student from Eastward:/student_details.csv delimiter ',' csv header;"        

How to import CSV file into Postgresql using control-line

• psql -d dbname -U username -c: Information technology enables y'all to issue queries from your command prompt or terminal to the Postgresql database direct.
• It shows the result of queries in the same terminal where:
• -d for the name of the database,
• -U for user of the database and
• -c for the command that you desire to perform on the database.

Also read: PostgreSQL Driblet TABLE

How to import csv file into postgresql using pgadmin

To import CSV file into Postgresql using pgadmin, follow these steps:

• First, open pgAdmin and select the databse that contains your tabular array.

In the above picture, I have selected the Postgres database.

• Next, select the table that you want to employ for loading CSV files by expanding the Schemas section of the Postgres database. And then right-click on the tabular array to select the "Import/Export" option.

How to import CSV file into Postgresql using pgadmin

• A dialog box appears after clicking on Import/Consign and fill the data according to your file location and blazon of file.

How to import CSV file into Postgresql using pgadmin

In the higher up picture, nosotros have implemented the following tasks.

( 1 ) alter from Export to Import, ( 2 ) Browse the path of CSV file, ( 3 ) Select the format of the file, ( iv ) Toggle header if it contains a header, ( five ) Select delimiter from the list that separates the information of the CSV file.

• Now, click on the OK button or hitting Enter from your keyboard.
• You accept imported information into the table, verify it by a query select * from educatee.

How to import CSV file into Postgresql using pgadmin

You may as well like reading the following Postgresql articles.

• PostgreSQL Driblet Cavalcade
• Postgresql date comparison
• Postgresql prepare user password
• PostgreSQL INSERT Multiple Rows
• PostgreSQL INSERT INTO table
• Postgresql change cavalcade data type
• How to find primary column name in Postgresql

So in this tutorial, we have learned about "How to import CSV file into Postgresql database" using different approaches with examples. And we have covered the following topic:

• How to import csv file into postgresql database
• How to import csv file into postgresql database using python
• How to import csv file into postgresql database using java
• How to import csv file in postgresql using command line
• How to import csv file in postgresql using pgadmin

After working for more than than 15 years in the Software field, peculiarly in Microsoft technologies, I have decided to share my expert knowledge of SQL Server. Cheque out all the SQL Server and related database tutorials I have shared here. Most of the readers are from countries like the U.s.a. of America, the United Kingdom, New Zealand, Australia, Canada, etc. I am also a Microsoft MVP. Check out more here.

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Source: https://sqlserverguides.com/how-to-import-csv-file-into-postgresql/

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