Better support for SET statements and MySQL variables
#214
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This traversal produces a natural ordering that corresponds to the original parsed input. It also aligns with CSS selector behavior. This is useful in situations when we need to reconstract or retrieve a fragment of the original input with tokens in the correct order.
…cient at the moment
| && WP_MySQL_Lexer::NAMES_SYMBOL === $part->id | ||
| ) { | ||
| // "SET NAMES ..." is a no-op for now. | ||
| // TODO: Validate charset compatibility with UTF-8. |
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should we call _doing_it_wrong to log a warning?
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@adamziel We'll need to validate it somehow, but I think that should be part of #192. If we do it properly (getting a list of all commonly supported charsets and, for each one of them evaluating whether they are UTF-8 compatible or not), then maybe we can even throw an error. Or at least a warning.
We can't use directly _doing_it_wrong as that's WP-specific, but we want the driver to be more universal.
| $value = str_replace( "''", "'", $value ); | ||
| $value = substr( $value, 1, -1 ); | ||
| /* | ||
| * Some MySQL system variables values can be set using an unquoted pure |
| /* | ||
| * Handle ON/OFF values. They are accepted as both strings and keywords. | ||
| * | ||
| * @TODO: This is actually variable-specific and depends on the its type. |
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@adamziel Yeah... So to support the system variables better in the future, we'll need a list of them, their types, etc. And for some of them, we should implement whatever behavior they modify.
| $name = $this->unquote_sqlite_identifier( | ||
| $this->translate( $user_variable->get_first_child() ) | ||
| ); | ||
| $name = strtolower( substr( $name, 1 ) ); // Remove '@', normalize case. |
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any chance we get a double @@ here?
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@adamziel I think that should be excluded by the grammar — single @ is user variable, double @ is system variable.
| * @return mixed The value of the expression. | ||
| */ | ||
| public function evaluate_expression( WP_Parser_Node $node ) { | ||
| // To support expressions, we'll use a SQLite query. |
Co-authored-by: Adam Zieliński <[email protected]>
This pull request implements better support for MySQL
SETstatements.It also implements additional related functionality and resolves some related issues:
CONCAT('a', 'b')to('a' || 'b'), we need to use the originalCONCAT('a', 'b')string as the column name. In other words,SELECT CONCAT('a', 'b')will be translated toSELECT ('a' || 'b') AS ’CONCAT('a', 'b')’. This is also needed when selecting user and system variables (see the items below).SET NAMES,SET CHARSET, andSET CHARACTER SETare a no-op now, with aTODOto implement some validation logic in Charset and collation support #192.SET @my_var = ...,SELECT @my_var).SET time_zone = ...,SET @@time_zone = ..., ,SET @@session.time_zone = ...,SELECT @@time_zone,SELECT @@session.time_zone, etc.). The variables are not yet interpreted in any way, and they are not merged with global system variables at the moment.