wpdb::get_col_charset( string $table, string $column ): string|false|WP_Error
- Since
- 4.2.0
- Source
wp-includes/class-wpdb.php:3296
Compatibility
- WordPress
- since 4.2.0
- PHP
- 7.4–8.6-dev
- 6.7.7
- 6.8.8
- 6.9.7
- 7.0.4
- 7.1.0
Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.
Parameters
$tablestring- Table name.
$columnstring- Column name.
Return value
string|false|WP_Error- Column character set as a string. False if the column has no character set. WP_Error object if there was an error.
Performance profile
How much work a call to wpdb::get_col_charset() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.
- Cost class
- Trivial
- Scaling
- Constant
- Instructions
- 20–55
- Plugin surface
- 1 hook
- Called by
- 2
Touches nothing outside its own arguments.
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 65.
Third-party callbacks on 'pre_get_col_charset' run inside this call, and their cost is not bounded by anything here.
2 places in core call this, so the cost is paid more often than your own code shows.
What it touches
- hookthird-party callbacks
apply_filters()called directly
What one call costs · 4 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost wpdb::get_col_charset() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
| always | 20–37 | strtolower(), strtolower(), apply_filters() |
$charset === null && !empty($value) && empty($tablekey) | 33–45 | strtolower(), strtolower(), apply_filters(), ->get_table_charset(), is_wp_error() |
$charset === null && !empty($value) && !empty($tablekey) && !empty($columnkey) | 47 | strtolower(), strtolower(), apply_filters(), explode() |
$charset === null && !empty($value) && !is_wp_error() && !empty($columnkey) | 55 | strtolower(), strtolower(), apply_filters(), ->get_table_charset(), is_wp_error(), explode() |
Across PHP versions
Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 65 instructions, 20–55 executed per call, 7 branches. The work does not change between versions.
An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.
Hooks and filters fired · 1
One hook fires while wpdb::get_col_charset() runs, in this order:
- apply_filters( pre_get_col_charset )filterline 3312 (+16 into the body)
Filters the column charset value before the DB is checked.
Uses · 3
- apply_filters()Calls the callback functions that have been added to a filter hook.
- is_wp_error()Checks whether the given variable is a WordPress Error.
- wpdb::get_table_charset()Retrieves the character set for the given table.
Used by · 2
- wpdb::process_field_charsets()Adds field charsets to field/value/format arrays generated by wpdb::process_field_formats().
- wpdb::strip_invalid_text_for_column()Strips any invalid characters from the string for a given table and column.
Source code
public function get_col_charset( $table, $column ) { $tablekey = strtolower( $table ); $columnkey = strtolower( $column ); /** * Filters the column charset value before the DB is checked. * * Passing a non-null value to the filter will short-circuit * checking the DB for the charset, returning that value instead. * * @since 4.2.0 * * @param string|null|false|WP_Error $charset The character set to use. Default null. * @param string $table The name of the table being checked. * @param string $column The name of the column being checked. */ $charset = apply_filters( 'pre_get_col_charset', null, $table, $column ); if ( null !== $charset ) { return $charset; } // Skip this entirely if this isn't a MySQL database. if ( empty( $this->is_mysql ) ) { return false; } if ( empty( $this->table_charset[ $tablekey ] ) ) { // This primes column information for us. $table_charset = $this->get_table_charset( $table ); if ( is_wp_error( $table_charset ) ) { return $table_charset; } } // If still no column information, return the table charset. if ( empty( $this->col_meta[ $tablekey ] ) ) { return $this->table_charset[ $tablekey ]; } // If this column doesn't exist, return the table charset. if ( empty( $this->col_meta[ $tablekey ][ $columnkey ] ) ) { return $this->table_charset[ $tablekey ]; } // Return false when it's not a string column. if ( empty( $this->col_meta[ $tablekey ][ $columnkey ]->Collation ) ) { return false; } list( $charset ) = explode( '_', $this->col_meta[ $tablekey ][ $columnkey ]->Collation ); return $charset; }Changelog
Introduced in 4.2.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
About this page
- Parsed data
- Generated from the wordpress-develop 6.7.7 tag, from
src/wp-includes/class-wpdb.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it. - Corrections
- Something wrong on this page? Report it and it gets fixed in the next regeneration.