摘要:

monetdb-relation-关键数据结构-记录

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 intcard: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 intflag: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;