Enforcing Case Sensitivity on Columns in MariaDB Tables

Here's why you can't directly set case-sensitivity on a column:

• MariaDB Limitations: Currently, MariaDB doesn't offer a direct way to modify just the case-sensitivity aspect of a column.

There is a workaround, though:

1. Modify Column Definition: You can use the ALTER TABLE statement with the MODIFY COLUMN clause to redefine the entire column, including its data type, default value, and importantly, the collation. This essentially creates a new column with the desired case-sensitivity and copies the data across.

Important things to remember:

• This approach can be time-consuming for large tables.
• Ensure the chosen collation is supported by your MariaDB version.
• Back up your data before making any schema changes.

-- Assuming your table is named 'my_table' and the column you want to modify is 'my_column'

-- 1. Backup your table (recommended)
ALTER TABLE my_table ENGINE = InnoDB;  -- InnoDB is for illustration, use your table engine

-- 2. Alter the table to modify the column definition
ALTER TABLE my_table
MODIFY COLUMN my_column VARCHAR(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin;

-- This example uses utf8mb4 character set and utf8mb4_bin collation
-- Choose a collation that suits your data and is supported by your MariaDB version

Explanation:

1. We start with a comment assuming the table name and the column you want to modify.
2. The first line is optional but recommended. It backs up your table using the InnoDB engine (replace with your engine if different). This step ensures you have a copy in case something goes wrong during the modification.
3. The second line uses the ALTER TABLE statement with the MODIFY COLUMN clause. This clause allows us to redefine an existing column.
   • my_column VARCHAR(255): This specifies the column name, data type (VARCHAR(255) in this case), and maximum length.
   • CHARACTER SET utf8mb4: This defines the character set used for storing data in the column.
   • COLLATE utf8mb4_bin: This sets the collation to utf8mb4_bin, which is a case-sensitive collation for the utf8mb4 character set.

Important Notes:

• Remember to replace my_table and my_column with your actual table and column names.
• Choose a collation that aligns with your data and is compatible with your MariaDB version. You can check available collations using SHOW COLLATION command.
• This approach essentially creates a new column definition with the desired collation and copies data from the old column. This can take time for large tables.

1. Case-Sensitive Comparisons During Queries:

   • While you can't inherently make the column case-sensitive, you can perform case-sensitive comparisons within your queries using the BINARY keyword. Here's an example:

   SELECT * FROM my_table
   WHERE BINARY my_column = 'ThisIsCaseSensitive';
   

   In this example, the BINARY keyword ensures a byte-by-byte comparison, making the search case-sensitive.

2. Use a Separate Case-Sensitive Column:

Both these alternatives have limitations:

• Case-Sensitive Comparisons: This approach only affects specific queries and doesn't inherently change the column behavior.
• Separate Case-Sensitive Column: This requires additional storage space and maintenance for the new column.