Check new data in database

To check for new data in a database, you can use various methods depending on the type of database and the programming language you are using. Here are a few examples:

SQL

SELECT statement with a WHERE clause: You can use a SELECT statement with a WHERE clause to retrieve data that has been inserted or updated since a specific timestamp.
```
SELECT * FROM table_name WHERE timestamp > (SELECT MAX(timestamp) FROM table_name - INTERVAL 1 DAY);
```
This query retrieves all rows from table_name where the timestamp column is greater than the maximum timestamp value minus one day.
ROW_NUMBER() function: You can use the ROW_NUMBER() function to assign a unique number to each row in the result set, and then filter the results to only include rows with a row number greater than a specific value.
```
WITH new_data AS (
SELECT *, ROW_NUMBER() OVER (ORDER BY timestamp) AS row_num
FROM table_name
)
SELECT * FROM new_data WHERE row_num > (SELECT COUNT(*) FROM table_name - INTERVAL 1 DAY);
```
This query uses a Common Table Expression (CTE) to assign a row number to each row in table_name, and then filters the results to only include rows with a row number greater than the number of rows in table_name minus one day.

NoSQL databases

MongoDB: You can use the find() method with a query filter to retrieve data that has been inserted or updated since a specific timestamp.
```
db.collection.find({ timestamp: { $gt: ISODate().getTime() - 86400000 } });
```
This query retrieves all documents from collection where the timestamp field is greater than the current timestamp minus one day.
Cassandra: You can use the SELECT statement with a WHERE clause to retrieve data that has been inserted or updated since a specific timestamp.
```
SELECT * FROM table_name WHERE timestamp > (SELECT MAX(timestamp) FROM table_name - INTERVAL 1 DAY);
```
This query retrieves all rows from table_name where the timestamp column is greater than the maximum timestamp value minus one day.

Programming languages

Python: You can use the pandas library to read data from a database and then filter the results to only include new data.
```
import pandas as pd
```

Read data from database

df = pd.read_sql_query("SELECT * FROM table_name", db_connection)

Filter data to only include new data

new_data = df[df['timestamp'] > (df['timestamp'].max() - pd.Timedelta(days=1))]

This code reads data from `table_name` using `pandas` and then filters the results to only include rows with a `timestamp` greater than the maximum `timestamp` value minus one day.

2. **Java**: You can use the `JDBC` API to execute a query that retrieves new data from a database.
```java
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("SELECT * FROM table_name WHERE timestamp > (SELECT MAX(timestamp) FROM table_name - INTERVAL 1 DAY)");

This code executes a query that retrieves all rows from table_name where the timestamp column is greater than the maximum timestamp value minus one day.

These are just a few examples of how you can check for new data in a database. The specific method you use will depend on the type of database and the programming language you are using.

NewsBreakers

Check new data in database

Read data from database

Filter data to only include new data