### Basic YDBPython Usage Example

Source: https://gitlab.com/yottadb/lang/ydbpython/-/blob/master/README.md

Demonstrates basic operations like creating keys, setting and getting values, and deleting nodes using YDBPython.

```python
import yottadb

# Create Key objects for conveniently accessing and manipulating database nodes
key1 = yottadb.Key('^hello')  # Create a key referencing the global variable '^hello'

print(f"{key1}: {key1.value}")  # Display current value of '^hello'
key1.value = b'Hello world!'  # Set '^hello' to 'Hello world!'
print(f"{key1}: {key1.value}")

key2 = yottadb.Key('^hello')['cowboy']  # Add a 'cowboy' subscript to the global variable '^hello', creating a new key
key2.value = 'Howdy partner!'  # Set '^hello('cowboy') to 'Howdy partner!'
print(f"{key2}: {key2.value}")

key3 = yottadb.Key('^hello')['chinese']  # Add a second subscript to '^hello', creating a third key
key3.value = bytes('你好世界!', encoding="utf-8")  # The value can be set to anything that can be encoded to `bytes`
print(key3, str(key3.value, encoding="utf-8"))  # Returned values are `bytes` objects, and so may need to be encoded

for subscript in key1.subscripts:  # Loop through all the subscripts of a key
    sub_key = key1[subscript]
    print(f"{sub_key}: {sub_key.value}")

key1.delete_node()  # Delete the value of '^hello', but not any of its child nodes

print(f"{key1}: {key1.value}")  # No value is printed
for subscript in key1.subscripts:  # The values of the child nodes are still in the database
    sub_key = key1[subscript]
    print(f"{sub_key}: {sub_key.value}")

key1.value = 'Hello world!'   # Reset the value of '^hello'
print(f"{key1}: {key1.value}")  # Prints the value
key1.delete_tree() # Delete both the value at the '^hello' node and all of it's children
print(f"{key1}: {key1.value}")  # Prints no value
for subscript in key1.subscripts:  # Loop terminates immediately and displays no subscripts
    sub_key = key1[subscript]
    print(sub_key, sub_key.value)
```

--------------------------------

### Install Pre-commit Hook

Source: https://gitlab.com/yottadb/lang/ydbpython/-/blob/master/README.md

Installs the pre-commit hook for contributing to YDBPython. Requires black to be installed.

```bash
ln -s ../../tools/git_hooks/pre-commit.sh .git/hooks/pre-commit
```

--------------------------------

### Run YDBPython Test Suite

Source: https://gitlab.com/yottadb/lang/ydbpython/-/blob/master/README.md

Executes the YDBPython test suite after installation from source. May require cleanup between test runs.

```bash
python -m pytest
```

--------------------------------

### Cleanup Test Artifacts

Source: https://gitlab.com/yottadb/lang/ydbpython/-/blob/master/README.md

Removes files listed in .gitignore to clean up between test runs. Use with caution as it deletes core files.

```bash
for artifact in $(cat .gitignore); do rm -rf $artifact; done
```

--------------------------------

### Implement Simple Database Transaction in YDBPython

Source: https://gitlab.com/yottadb/lang/ydbpython/-/blob/master/README.md

Use the @yottadb.transaction decorator to define a function that performs database operations. This snippet demonstrates setting local variables and handling potential rollback or restart exceptions.

```python
import yottadb

@yottadb.transaction
def simple_transaction(value):
    # Set values directly with the set() function
    yottadb.set('test1', value=value)  # Set the local variable 'test1' to the given value
    yottadb.set('test2', value=value)  # Set the local variable 'test2' to the given value
    condition_a = False
    condition_b = False
    if condition_a:
        # When a yottadb.YDBTPRollback exception is raised YottaDB will rollback the transaction
        # and then propagate the exception to the calling code.
        raise yottadb.YDBTPRollback("reason for the rollback")
    elif condition_b:
        # When a yottadb.YDBTPRestart exception is raised YottaDB will call the transaction again.
        # Warning: This code is intentionally simplistic. An infinite loop will occur
        #           if yottadb.YDBTPRestart is continually raised
        raise yottadb.YDBTPRestart()
    else:
        return yottadb.YDB_OK  # Success, transaction will be committed


simple_transaction(b'test', db)
print(f"{db[b'test1']}: {db[b'test1'].value}")
print(f"{db[b'test2']}: {db[b'test2'].value}")
```

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