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describe_table()

public function describe_table(string $table, bool $names_only = false): array|false

Description

Retrieves structural information about a database table using MySQL's DESCRIBE statement. This method can return either detailed column information or just column names. It's useful for dynamic form generation, validation, and understanding table schema at runtime.

Parameters

Parameter Type Description Default Required
table string The name of the table to describe. - Yes
names_only bool If true, returns only column names. If false, returns full column details. false No

Return Value

Type Description
array|false Returns array of column details/names on success, or false on failure (e.g., table doesn't exist).

Column Details Structure

When $names_only = false, each array element contains these keys:

Key Description Example Value
Field Column name 'id', 'username', 'email'
Type Data type with length/precision 'int(11)', 'varchar(255)', 'decimal(10,2)'
Null Whether NULL values are allowed ('YES' or 'NO') 'NO', 'YES'
Key Index information (PRI, UNI, MUL, or empty) 'PRI', 'UNI', 'MUL', ''
Default Default value or NULL 'NULL', 'CURRENT_TIMESTAMP', '0'
Extra Additional information (auto_increment, etc.) 'auto_increment', ''

Example #1: Getting Full Column Details

The code sample below demonstrates how to retrieve complete column information from the 'users' table.

Example #2: Getting Only Column Names

The code sample below demonstrates how to retrieve just the column names from the 'products' table.

Example #3: Using Column Information for Validation

The code sample below demonstrates how to use column information to validate data before insertion.

Important Notes

  • The $table parameter is required.
  • Returns false on failure (e.g., table doesn't exist, database error).
  • Uses MySQL's DESCRIBE statement which is MySQL-specific (not portable to other databases).
  • When $names_only = true, returns a simple indexed array of column names.
  • When $names_only = false, returns an array of associative arrays with column details.
  • Useful for dynamic applications that need to adapt to different table structures.
  • Consider caching results if calling frequently on the same table.
  • For more detailed metadata, consider using SHOW FULL COLUMNS FROM or querying INFORMATION_SCHEMA directly.