sql_foreign_key_constraint.h

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#pragma once
 
class THD;
struct TABLE;
struct Table_share_foreign_key_info;
 
enum class enum_fk_dml_type {
  FK_INSERT,
  FK_UPDATE,
  FK_DELETE,
  // REPLACE executes as DELETE (of the conflicting row) + INSERT (the new row)
  // For the DELETE, FK checks must use the before-image (record[1]) to build
  // the FK search key; FK_DELETE_REPLACE signals this path (not record[0],
  // the after-image).
  FK_DELETE_REPLACE
};
 
/**
 * @brief Check if TABLE instance for foreign key is already opened.
 *
 * @param thd          Thread handle.
 * @param db_name      DB name.
 * @param table_name   Table name.
 * @param fk_name      Foreign key name.
 * @param[out] is_unused_table  Is set true if table exists in open table
 *                              list but not in use. For instance tables locked
 *                              under lock table, exists in open table list but
 *                              not used. query_id for such tables is reset to
 *                              0 after statement execution.
 *
 * @return true        If table for foreign key is already opened.
 * @return false       If table is not opened.
 */
bool is_foreign_key_table_opened(THD *thd, const char *db_name,
                                 const char *table_name, const char *fk_name,
                                 bool *is_unused_table);
 
/**
 * @brief Check all foreign key constraints on parent tables for DML operation
 *        on a child table.
 *
 * @param thd           Thread handle.
 * @param table_c       TABLE instance of a child table.
 * @param dml_type      DML operation type.
 * @param ignore_fk     Skip FK check for this foreign key info
 *
 * @return true         On error.
 * @return false        On Success.
 */
bool check_all_parent_fk_ref(
    THD *thd, const TABLE *table_c, enum_fk_dml_type dml_type,
    const Table_share_foreign_key_info *ignore_fk = nullptr);
 
/**
 * @brief Check all foreign key constraints on child tables for DML operation
 *        on a parent table.
 *
 * @param thd           Thread handle.
 * @param table_p       TABLE instance of a parent table.
 * @param dml_type      DML operation type.
 *
 * @return true         On error.
 * @return false        On Success.
 */
bool check_all_child_fk_ref(THD *thd, const TABLE *table_p,
                            enum_fk_dml_type dml_type);