• SAVEPOINT name —> marks a save point • COMMIT —> making all pending changes permanent; • ROLLBACK —> discharges all pending changes to prev commit • ROLLBACK TO name —> rolls back changes to savepoint
Here is what the above code is Doing:
1. Create a connection to the database.
2. Create a cursor object.
3. Execute the CREATE TABLE statement.
4. Execute the INSERT statement.
5. Commit the changes to the database.
6. Close the database connection.
(NVL) replaces NULL values with same type default value provided. For Example = Select NVL(commission_percentage, 0) From Employees; Here is what the above code is Doing: 1. The NVL function is used to replace a NULL value with a default value. 2. The NVL function takes two arguments. 3. The first argument is the value…
#Integrated Security sqlcmd -S Serverinstance -E -i import_file.sql #UserName and Password sqlcmd -S -U sa -P sapassword -i inputquery_file_name -o outputfile_name Here is what the above code is Doing: 1. The -S switch is used to specify the server name. 2. The -E switch is used to specify that you want to use Windows Authentication….
SELECT name, COUNT(email) FROM users GROUP BY email HAVING COUNT(email) > 1 Here is what the above code is Doing: 1. We’re selecting the name and email columns from the users table. 2. We’re grouping the results by email. 3. We’re filtering the results to only return groups of emails that appear more than once.
SELECT (DBMS_LOB.getlength(your_column_name))/1024/1024 AS SizeMB FROM your_table Here is what the above code is Doing: 1. First, we’re selecting the column name that we want to get the size of. 2. Then, we’re using the DBMS_LOB.getlength function to get the length of the column. 3. Then, we’re dividing the length by 1024 to get the size…
NoSQL systems are also sometimes called “Not only SQL” to emphasize that they may support SQL-like query languages or sit alongside SQL databases in polyglot-persistent architectures. Here is what the above code is Doing: 1. We’re importing the MongoClient class from the pymongo module. 2. We’re creating a MongoClient instance on port 27017. 3. We’re…
mysql -u yourusername -p yourpassword yourdatabase < text_file Here is what the above code is Doing: 1. mysql -u yourusername -p yourpassword yourdatabase 2. < text_file The first line is the command to log into the database. The second line is the command to read the text file.