sql - reading from textfile and then inserting record to oracle table

Sql - reading from textfile and then inserting record to oracle table

To read from a text file and insert records into an Oracle table, you typically have several approaches depending on your environment and requirements. Below are steps for a common method using SQL*Loader, which is a utility provided by Oracle for bulk loading data from flat files into Oracle database tables.

Using SQL*Loader to Load Data

SQLLoader is a powerful tool that Oracle provides for loading data from external files into Oracle tables. Here's a basic example of how you can use SQLLoader:

Step 1: Prepare Your Text File

First, ensure your text file (data.txt, for example) is formatted correctly. Each line should correspond to a record you want to insert into your Oracle table, with columns separated by a delimiter (e.g., comma, pipe, tab).

Example data.txt:

1001,John,Doe,25 1002,Jane,Smith,30 1003,Michael,Johnson,28

Step 2: Create a Control File

SQL*Loader uses a control file (.ctl) to specify how to load the data into Oracle tables. Create a control file (load_data.ctl, for example) with the following content:

LOAD DATA INFILE 'data.txt' -- Path to your data file APPEND INTO TABLE your_table_name -- Name of your Oracle table FIELDS TERMINATED BY ',' -- Field delimiter in your data file ( column1, column2, column3, column4 )

Replace your_table_name with the actual name of your Oracle table and adjust column1, column2, etc., to match your table's columns.

Step 3: Run SQL*Loader

Run SQL*Loader from the command line or terminal. Navigate to the directory containing your control file (load_data.ctl) and execute:

sqlldr username/password@database control=load_data.ctl

Replace username, password, and database with your Oracle database credentials and connection details.

Step 4: Verify Data

After SQL*Loader completes successfully, verify that the data has been inserted into your Oracle table by querying it:

SELECT * FROM your_table_name;

Alternative Approaches

  • External Tables: Oracle also supports using external tables to query data directly from external files without loading them into Oracle tables permanently.

  • PL/SQL: You can use PL/SQL procedures or scripts to read data from a file line-by-line and insert records into Oracle tables using UTL_FILE package for file operations.

  • Third-Party ETL Tools: For more complex scenarios or integration with other systems, consider using Oracle Data Integrator (ODI) or other ETL (Extract, Transform, Load) tools.

Considerations

  • Ensure the text file (data.txt) and control file (load_data.ctl) are accessible and have correct permissions.

  • Handle errors and data validation appropriately, especially when dealing with large datasets.

  • Use appropriate data types and handle special characters or formatting issues in your data files.

By following these steps, you can efficiently load data from a text file into an Oracle database table using SQL*Loader. Adjust the approach based on your specific requirements and environment setup.

Examples

  1. Load data from a text file into an Oracle table using SQL Loader:

    LOAD DATA INFILE 'data.txt' INTO TABLE my_table FIELDS TERMINATED BY ',' (col1, col2, col3);

    Description: Uses SQL Loader to load data from a comma-separated text file (data.txt) into my_table in Oracle. Adjust FIELDS TERMINATED BY ',' and column names (col1, col2, col3) based on your file format and table structure.

  2. Insert records from a text file into an Oracle table using SQL and external tables:

    CREATE TABLE ext_table ( col1 VARCHAR2(50), col2 VARCHAR2(50), col3 VARCHAR2(50) ) ORGANIZATION EXTERNAL ( TYPE ORACLE_LOADER DEFAULT DIRECTORY data_dir ACCESS PARAMETERS ( RECORDS DELIMITED BY NEWLINE FIELDS TERMINATED BY ',' MISSING FIELD VALUES ARE NULL ( col1 CHAR(50), col2 CHAR(50), col3 CHAR(50) ) ) LOCATION ('data.txt') ); INSERT INTO my_table (col1, col2, col3) SELECT col1, col2, col3 FROM ext_table;

    Description: Creates an external table (ext_table) in Oracle using SQL Loader parameters to define how data is read from data.txt. Inserts records from ext_table into my_table. Adjust column types and sizes (VARCHAR2(50), CHAR(50)) according to your data and table structure.

  3. Read and insert records from a text file line by line using PL/SQL:

    DECLARE file_handle UTL_FILE.FILE_TYPE; file_name VARCHAR2(100) := 'data.txt'; line_text VARCHAR2(4000); BEGIN file_handle := UTL_FILE.FOPEN('DATA_DIR', file_name, 'r'); LOOP UTL_FILE.GET_LINE(file_handle, line_text); -- Parse line_text and insert into my_table -- INSERT INTO my_table (col1, col2, col3) VALUES (value1, value2, value3); -- Exit loop when no more lines to read EXIT WHEN UTL_FILE.IS_OPEN(file_handle) = 0; END LOOP; UTL_FILE.FCLOSE(file_handle); END; /

    Description: Uses PL/SQL to open data.txt from a directory (DATA_DIR), read each line, parse the data (line_text), and insert into my_table. Adjust parsing and insertion logic (INSERT INTO my_table) based on your file format and table schema.

  4. Insert records from a text file using SQL and Oracle SQL Developer:

    BEGIN INSERT INTO my_table (col1, col2, col3) SELECT col1, col2, col3 FROM EXTERNAL 'C:\path\to\data.txt' WITH ( FORMAT CSV FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"' MISSING FIELD VALUES ARE NULL REJECT ROWS WITH ALL NULL FIELDS ); END;

    Description: Executes an INSERT INTO statement in Oracle SQL Developer to insert records from a CSV formatted text file (data.txt) into my_table. Adjust file path and delimiter (FIELDS TERMINATED BY ',', OPTIONALLY ENCLOSED BY '"') as per your data format.

  5. Use SQL*Loader to insert data from a text file with control file:

    sqlldr username/password@database control=loader.ctl

    Description: Executes SQL*Loader command-line utility to load data from loader.ctl control file into an Oracle table. Modify loader.ctl file to specify data file (INFILE) and table columns (INTO TABLE).

  6. Load data from a text file using external tables and INSERT INTO SELECT:

    CREATE TABLE ext_table ( col1 VARCHAR2(50), col2 VARCHAR2(50), col3 VARCHAR2(50) ) ORGANIZATION EXTERNAL ( TYPE ORACLE_LOADER DEFAULT DIRECTORY data_dir ACCESS PARAMETERS ( RECORDS DELIMITED BY NEWLINE FIELDS TERMINATED BY ',' MISSING FIELD VALUES ARE NULL ( col1 CHAR(50), col2 CHAR(50), col3 CHAR(50) ) ) LOCATION ('data.txt') ); INSERT INTO my_table (col1, col2, col3) SELECT col1, col2, col3 FROM ext_table;

    Description: Creates an external table (ext_table) using Oracle Loader parameters to define how data is read from data.txt. Inserts records from ext_table into my_table. Adjust column types and sizes (VARCHAR2(50), CHAR(50)) according to your data and table structure.

  7. Insert data into Oracle table from text file using SQL Loader and control file:

    LOAD DATA INFILE 'data.txt' INTO TABLE my_table FIELDS TERMINATED BY ',' (col1, col2, col3)

    Description: Uses SQL Loader to insert data from data.txt into my_table. The control file specifies how columns (col1, col2, col3) are mapped from the text file.

  8. Load text file data into Oracle table using external tables and SQL query:

    CREATE TABLE ext_table ( col1 VARCHAR2(50), col2 VARCHAR2(50), col3 VARCHAR2(50) ) ORGANIZATION EXTERNAL ( TYPE ORACLE_LOADER DEFAULT DIRECTORY data_dir ACCESS PARAMETERS ( RECORDS DELIMITED BY NEWLINE FIELDS TERMINATED BY ',' MISSING FIELD VALUES ARE NULL ( col1 CHAR(50), col2 CHAR(50), col3 CHAR(50) ) ) LOCATION ('data.txt') ); INSERT INTO my_table (col1, col2, col3) SELECT col1, col2, col3 FROM ext_table;

    Description: Creates an external table (ext_table) in Oracle using Oracle Loader parameters to specify how data is read from data.txt. Inserts records from ext_table into my_table. Adjust column types and sizes (VARCHAR2(50), CHAR(50)) as needed.

  9. Insert records into Oracle table from text file using PL/SQL and UTL_FILE package:

    DECLARE file_handle UTL_FILE.FILE_TYPE; file_name VARCHAR2(100) := 'data.txt'; line_text VARCHAR2(4000); BEGIN file_handle := UTL_FILE.FOPEN('DATA_DIR', file_name, 'r'); LOOP UTL_FILE.GET_LINE(file_handle, line_text); -- Parse line_text and insert into my_table -- INSERT INTO my_table (col1, col2, col3) VALUES (value1, value2, value3); -- Exit loop when no more lines to read EXIT WHEN UTL_FILE.IS_OPEN(file_handle) = 0; END LOOP; UTL_FILE.FCLOSE(file_handle); END; /

    Description: Uses PL/SQL and the UTL_FILE package to open data.txt from a directory (DATA_DIR), read each line, parse the data (line_text), and insert into my_table. Adjust parsing and insertion logic (INSERT INTO my_table) based on your file format and table schema.

  10. Insert records into Oracle table from text file using SQL Developer and INSERT INTO SELECT:

    INSERT INTO my_table (col1, col2, col3) SELECT col1, col2, col3 FROM EXTERNAL 'C:\path\to\data.txt' WITH ( FORMAT CSV FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"' MISSING FIELD VALUES ARE NULL REJECT ROWS WITH ALL NULL FIELDS );

    Description: Executes an INSERT INTO statement in Oracle SQL Developer to insert records from a CSV formatted text file (data.txt) into my_table. Adjust file path and delimiter (FIELDS TERMINATED BY ',', OPTIONALLY ENCLOSED BY '"') as per your data format.

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