This task is intended to simplify the work for CREATE PACKAGE (see MDEV-10591), as well as to fix minor known problems in the underlying parser grammar.
There are a few difficulties in the grammar for CREATE for VIEW, TRIGGER, EVENT, PROCEDURE, FUNCTION.
- The grammar for the mentioned objects is implemented with help of the rule view_or_trigger_or_sp_or_event. The grammar for all other object types is implemented directly in the create: rule. This makes the grammar non-symmetric for various object types, which is hard to read and understand.
- We'll add CREATE PACKAGE soon. It will require the DEFINER clause. In the current grammar, it will have to go to view_or_trigger_or_sp_or_event again, and make the things even more complex.
- LEX::create_view_mode, LEX::create_view_algorithm, LEX::create_view_suid are initialized for all objects described in view_or_trigger_or_sp_or_event. For non-VIEW objects this initialization is redundant.
| create_or_replace
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{
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Lex->create_info.set($1);
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Lex->create_view_mode= ($1.or_replace() ? VIEW_CREATE_OR_REPLACE :
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VIEW_CREATE_NEW);
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Lex->create_view_algorithm= DTYPE_ALGORITHM_UNDEFINED;
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Lex->create_view_suid= TRUE;
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}
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view_or_trigger_or_sp_or_event { }
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Under terms of this task we'll do the following:
- For stricter data type control: introduce a new enum instead of pre-processor constants:
enum enum_view_suid
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{
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VIEW_SUID_INVOKER= 0,
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VIEW_SUID_DEFINER= 1,
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VIEW_SUID_DEFAULT= 2
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};
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class Create_view_info: public Sql_alloc
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{
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public:
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LEX_CSTRING select; // The SELECT statement of CREATE VIEW
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enum enum_view_create_mode mode;
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uint16 algorithm;
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uint8 check;
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enum enum_view_suid suid;
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Create_view_info(enum_view_create_mode mode_arg,
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uint16 algorithm_arg,
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enum_view_suid suid_arg)
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:select(null_clex_str),
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mode(mode_arg),
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algorithm(algorithm_arg),
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check(VIEW_CHECK_NONE),
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suid(suid_arg)
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{ }
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};
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- Remove the same members from LEX and add a pointer to Create_view_info instead. Create_view_info will be allocated on THD memory root only for CREATE VIEW or ALTER VIEW queries.
- Reduce the amount of duplicate C++ code used in .yy files by adding new methods in LEX:
bool add_alter_view(THD *thd, uint16 algorithm, enum_view_suid suid,
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Table_ident *table_ident);
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bool add_create_view(THD *thd, DDL_options_st ddl,
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uint16 algorithm, enum_view_suid suid,
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Table_ident *table_ident);
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- In sql_yacc.yy: remove grammar rules view_or_trigger_or_sp_or_event, definer_tail, no_definer_tail, view_tail
- In sql_yacc.yy: add new grammar branches directly into the create: rules, for VIEW, TRIGGER, PROCEDURE, FUNCTION, EVENT.
Note, when we add the CREATE PACKAGE statement later (see MDEV-10591), it will also be added directly to create:, together with its optional DEFINER clause.
- In sql_yacc.yy: fix the rules view_algorithm, view_suid, view_check_options to return values in $$, instead of setting thd->lex members directly. This is needed to pass these values to the new methods LEX::add_alter_view() and LEX::add_create_view().
- Do corresponding changes in sql_yacc_ora.yy.