Posts (page 17)
-
3 min readIn SPARQL, you can get today's date by using the built-in function NOW(). This function returns the current date and time in the format YYYY-MM-DDTHH:MM:SS. To extract only the date part, you can use the STRDT() and DATE() functions. Here is an example query to get today's date:SELECT (STRDT(DATE(NOW()), xsd:date) AS ?today) WHERE {your query here}[rating:a23f4a27-36f7-419b-8202-45e21c7afb2c]What is the key technique for accessing today's date in SPARQL.
-
6 min readTo add external variables to a SPARQL query, you need to use the BIND keyword followed by the variable assignment. You can use the BIND keyword to assign a value to a variable before executing the query. This allows you to use external variables in combination with the SPARQL query to retrieve specific results based on the assigned values. By binding external variables to the query, you can customize the results based on the input values provided.
-
4 min readWhen dealing with duplicate specific values in a SPARQL query, one approach is to use the DISTINCT keyword to ensure that only unique values are returned in the results. This can be particularly useful when querying a dataset that may contain duplicate entries for a given property or value.
-
6 min readTo run INSERT SPARQL queries from R, you can use the SPARQL package in R. First, you need to establish a connection to your SPARQL endpoint using the SPARQL function. Then, you can use the SPARQL function again to send your INSERT queries to the SPARQL endpoint. Make sure to enclose your SPARQL query within a triple-quoted string to avoid syntax errors. Finally, you can execute your query using the SPARQL function with the query argument set to your INSERT query.
-
7 min readIn SPARQL, conditions within a single query can be applied using the FILTER keyword. This keyword allows you to specify conditions that should be met in order for a particular result to be included in the query results. Conditions can be based on equality or inequality of values, comparison of numeric values, or checking for the presence of a certain value in a property value.
-
5 min readTo generate a SPARQL query to extract the publisher type, you will first need to identify the dataset or knowledge graph that contains the information about publishers. Once you have identified the dataset, you can write a SPARQL query that selects the publisher type for each publisher entity.The query will typically involve selecting the publisher entities and then selecting the type property for each publisher entity.
-
3 min readIn SPARQL, you can set the language of a literal variable using the LANG() function. This function takes a string literal as its argument and returns the language tag associated with that literal. For example, if you have a variable ?label that contains a string literal "Hello" with the language tag "en" (for English), you can use the expression LANG(?label) to retrieve the language tag "en".
-
5 min readTo add ALTER SESSION privileges to a user in Oracle SQL, you can use the GRANT statement. By executing the GRANT ALTER SESSION TO username; command, you can grant the user the ability to alter their session settings. This can be useful for users who need to adjust certain settings for their specific requirements during a session. To revoke this privilege, you can use the REVOKE statement in a similar manner.
-
3 min readIn Oracle, you can group query results based on a particular column using the GROUP BY clause in a SQL query. To group query results based on a job column, you can use a query like:SELECT job, COUNT(*) as total FROM employees GROUP BY job;This query will group all the employees based on their job titles and count the total number of employees in each job category.
-
5 min readTo use a window function with a case statement in Oracle SQL, you can include the case statement inside the window function's definition. This allows you to apply conditional logic to the rows in the window partition before the window function is applied.For example, if you want to calculate the sum of a column based on a condition using a window function, you can use a case statement within the sum function.
-
5 min readThe "not in" operator in Oracle SQL is used to retrieve records that do not match the values specified in a list. It functions as the opposite of the "in" operator.To use the "not in" operator, you would typically structure your query like this: SELECT column_names FROM table_name WHERE column_name NOT IN (value1, value2, ...);The values listed in the parentheses are the ones that you want to exclude from the query results.
-
4 min readTo connect to an Oracle database with Python, you can use the cx_Oracle library. First, you need to install the library by using pip install cx_Oracle. Then, you need to import the library in your Python script by using import cx_Oracle. Next, you can establish a connection to the Oracle database by using the cx_Oracle.connect() function and providing the necessary connection details such as username, password, host, and service name.