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| Spark Schema Generator from PostgreSQL Table Schema | ||
| This repository contains a Python script that generates a Spark StructType schema from a PostgreSQL table schema. | ||
| <!DOCTYPE html> | ||
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| Requirements | ||
| To use the script, you will need: | ||
| <body> | ||
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| Python 3.x | ||
| pyspark module | ||
| psycopg2 module | ||
| Access to a PostgreSQL database with the schema you want to generate a Spark schema for | ||
| Usage | ||
| Clone the repository to your local machine: | ||
| <h1>PySpark StructType schema generator from PostgreSQL table schema</h1> | ||
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| git clone https://github.com/yourusername/spark-postgres-schema-generator.git | ||
| Install the required modules: | ||
| <p>This Python program generates a PySpark StructType schema from a PostgreSQL table schema. The program connects to a PostgreSQL database, reads the schema of the specified table, and maps the PostgreSQL data types to the corresponding PySpark data types.</p> | ||
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| pip install pyspark psycopg2 | ||
| Open the generate_spark_schema.py file in your preferred text editor. | ||
| <h2>Prerequisites</h2> | ||
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| Update the following variables to match your PostgreSQL database connection details: | ||
| <ul> | ||
| <li>Python 3.x</li> | ||
| <li>PySpark</li> | ||
| <li>psycopg2</li> | ||
| <li>A PostgreSQL database with a table to generate the schema from</li> | ||
| </ul> | ||
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| <h2>Usage</h2> | ||
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| host = "localhost" | ||
| database = "mydb" | ||
| user = "myuser" | ||
| password = "mypassword" | ||
| Update the schema_name variable to match the name of the PostgreSQL schema you want to generate a Spark schema for: | ||
| <ol> | ||
| <li>Clone the repository: <code>git clone https://github.com/username/repo.git</code></li> | ||
| <li>Navigate to the directory: <code>cd repo</code></li> | ||
| <li>Edit the <code>config.ini</code> file to specify the PostgreSQL database connection parameters and the name of the table to generate the schema from</li> | ||
| <li>Run the program: <code>python generate_schema.py</code></li> | ||
| </ol> | ||
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| <h2>Configuring the program</h2> | ||
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| python generate_spark_schema.py | ||
| The script will print the generated Spark schema to the console. | ||
| <p>The program can be configured by editing the <code>config.ini</code> file. The file contains the following parameters:</p> | ||
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| Supported PostgreSQL Data Types | ||
| The script supports the following PostgreSQL data types: | ||
| <ul> | ||
| <li><code>host</code>: the hostname or IP address of the PostgreSQL server</li> | ||
| <li><code>port</code>: the port number of the PostgreSQL server</li> | ||
| <li><code>database</code>: the name of the PostgreSQL database</li> | ||
| <li><code>user</code>: the username to connect to the PostgreSQL database</li> | ||
| <li><code>password</code>: the password to connect to the PostgreSQL database</li> | ||
| <li><code>table_name</code>: the name of the table to generate the schema from</li> | ||
| </ul> | ||
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| ARRAY | ||
| bigint | ||
| boolean | ||
| bytea | ||
| character | ||
| character varying | ||
| date | ||
| double precision | ||
| integer | ||
| json | ||
| name | ||
| numeric | ||
| oid | ||
| smallint | ||
| text | ||
| timestamp with time zone | ||
| timestamp without time zone | ||
| <h2>Example output</h2> | ||
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| <p>The program generates output similar to the following:</p> | ||
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| Notes | ||
| The script assumes that any PostgreSQL column with a NOT NULL constraint is required in the Spark schema, and any column without a NOT NULL constraint is nullable in the Spark schema. | ||
| The script assumes that any PostgreSQL array column contains string elements. | ||
| The script assumes that any PostgreSQL numeric column has a specified precision and scale. If your database uses the default precision and scale for numeric columns, you may need to modify the script to handle this case. | ||
| The script assumes that the PostgreSQL schema name you provide has access to the tables you want to generate a Spark schema for. If you need to generate a schema for tables in a different schema, you will need to update the script accordingly. | ||
| <pre><code>StructType(List(StructField(id,IntegerType,true),StructField(name,StringType,true),StructField(age,IntegerType,true)))</code></pre> | ||
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| License | ||
| This project is licensed under the MIT License. See the LICENSE file for details. | ||
| <h2>Contributing</h2> | ||
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| <p>Contributions are welcome! Please submit a pull request if you'd like to contribute.</p> | ||
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| <h2>License</h2> | ||
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| <p>This program is licensed under the MIT license. See the <a href="LICENSE.md">LICENSE.md</a> file for details.</p> | ||
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| </body> | ||
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| </html> |