摘要:
monetdb-relation-关键数据结构-记录文章来源地址https://www.toymoban.com/news/detail-605770.html
关键数据结构:
expression_type
typedef enum expression_type {
e_atom,
e_column,
e_cmp,
e_func,
e_aggr,
e_convert,
e_psm
} expression_type;expression
typedef struct expression {
expression_type type; /* atom, cmp, func/aggr */
sql_exp_name alias;
void *l;
void *r;
void *f; /* func's and aggr's, also e_cmp may have have 2 arguments */
unsigned int flag; /* cmp types, PSM types/level */
unsigned int
card:2, /* card (0 truth value!) (1 atoms) (2 aggr) (3 multi value) */
freevar:4, /* free variable, ie binds to the upper dependent join */
intern:1,
anti:1,
ascending:1, /* order direction */
nulls_last:1, /* return null after all other rows */
zero_if_empty:1, /* in case of partial aggregator computation, some aggregators need to return 0 instead of NULL */
distinct:1,
semantics:1, /* is vs = semantics (nil = nil vs unknown != unknown), ranges with or without nil, aggregation with or without nil */
need_no_nil:1,
has_no_nil:1,
unique:1, /* expression has unique values, but it may have multiple NULL values! */
base:1,
ref:1, /* used to indicate an other expression may reference this one */
used:1, /* used for quick dead code removal */
symmetric:1; /* compare between symmetric */
sql_subtype tpe;
void *p; /* properties for the optimizer */
} sql_exp;ddl_statement
typedef enum ddl_statement {
ddl_output,
ddl_list,
ddl_psm,
ddl_exception,
ddl_create_seq,
ddl_alter_seq,
ddl_drop_seq,
ddl_alter_table_add_range_partition,
ddl_alter_table_add_list_partition,
ddl_release,
ddl_commit,
ddl_rollback,
ddl_trans,
ddl_create_schema,
ddl_drop_schema,
ddl_create_table,
ddl_drop_table,
ddl_create_view,
ddl_drop_view,
ddl_drop_constraint,
ddl_alter_table,
ddl_create_type,
ddl_drop_type,
ddl_drop_index,
ddl_create_function,
ddl_drop_function,
ddl_create_trigger,
ddl_drop_trigger,
ddl_grant_roles,
ddl_revoke_roles,
ddl_grant,
ddl_revoke,
ddl_grant_func,
ddl_revoke_func,
ddl_create_user,
ddl_drop_user,
ddl_alter_user,
ddl_rename_user,
ddl_create_role,
ddl_drop_role,
ddl_alter_table_add_table,
ddl_alter_table_del_table,
ddl_alter_table_set_access,
ddl_comment_on,
ddl_rename_schema,
ddl_rename_table,
ddl_rename_column,
ddl_maxops /* evaluated to the max value, should be always kept at the bottom */
} ddl_statement;operator_type
typedef enum operator_type {
op_basetable = 0,
op_table,
op_ddl,
op_project, /* includes order by */
op_select,
op_join,
op_left,
op_right,
op_full,
op_semi,
op_anti,
op_union,
op_inter,
op_except,
op_groupby,
op_topn,
op_sample,
op_insert, /* insert(l=table, r insert expressions) */
op_update, /* update(l=table, r update expressions) */
op_delete, /* delete(l=table, r delete expression) */
op_truncate, /* truncate(l=table) */
op_merge
} operator_type;relation
typedef struct relation {
sql_ref ref;
operator_type op;
void *l;
void *r;
list *exps;
list *attr; /* attributes: mark-joins return extra attributes */
/* later put all 'projection' attributes in here, ie for set ops, project/group/table/basetable by
* select/ (semi/anti/left/outer/right)join will use exps for predicates
* groupby will use exps for group by exps
* project can use exps for the order by bits
* topn/sample use exps for the input arguments of the limit/sample
*/
int nrcols; /* nr of cols */
unsigned int
flag:16,
card:4, /* 0, 1 (row), 2 aggr, 3 */
dependent:1, /* dependent join */
distinct:1,
processed:1, /* fully processed or still in the process of building */
outer:1, /* used as outer (ungrouped) */
grouped:1, /* groupby processed all the group by exps */
single:1;
/*
* Used by rewriters at rel_unnest, rel_optimizer and rel_distribute so a relation is not modified twice
* The list is kept at rel_optimizer_private.h Please update it accordingly
*/
uint8_t used;
void *p; /* properties for the optimizer, distribution */
} sql_rel;文章来源：https://www.toymoban.com/news/detail-605770.html
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