[Tarantool-patches] [PATCH v2 6/6] sql: extend result set with alias
Nikita Pettik
korablev at tarantool.org
Wed Dec 11 16:44:58 MSK 2019
Each column of result set can feature its name alias. For instance:
SELECT x + 1 AS add FROM ...;
In this case real name of resulting set column is "x + 1" meanwhile
"add" is its alias. This patch extends metadata with optional metadata
member which corresponds to column's alias.
Closes #4407
@TarantoolBot document
Title: extended SQL metadata
Before this patch metadata for SQL DQL contained only two fields:
name and type of each column of result set. Now it may contain
following properties:
- collation (in case type of resulting set column is string and
collation is different from default "none");
is encoded with IPROTO_FIELD_COLL (0x2) key in IPROTO_METADATA map;
in msgpack is encoded as string and held with MP_STR type;
- is_nullable (in case column of result set corresponds to space's
field; for expressions like x+1 for the sake of
simplicity nullability is omitted);
is encoded with IPROTO_FIELD_IS_NULLABLE key (0x3) in IPROTO_METADATA;
in msgpack is encoded as boolean and held with MP_BOOL type;
note that absence of this field implies that nullability is unknown;
- is_autoincrement (is set only for autoincrement column in result
set);
is encoded with IPROTO_FIELD_IS_AUNTOINCREMENT (0x4) key in IPROTO_METADATA;
in msgpack is encoded as boolean and held with MP_BOOL type;
- alias (if column of result set is specified with AS label);
is encoded with IPROTO_FIELD_ALIAS (0x5) key in IPROTO_METADATA map;
in msgpack is encoded as string and held with MP_STR type;
note that if there's no
This extended metadata is send only when PRAGMA full_metadata is
enabled. Otherwise, only basic (name and type) metadata is processed.
---
src/box/execute.c | 18 ++++++++++++++----
src/box/iproto_constants.h | 1 +
src/box/lua/execute.c | 9 +++++++--
src/box/lua/net_box.c | 6 +++++-
src/box/sql/select.c | 32 ++++++++++++++++++++++++++++----
src/box/sql/sqlInt.h | 3 +++
src/box/sql/vdbe.h | 3 +++
src/box/sql/vdbeInt.h | 1 +
src/box/sql/vdbeapi.c | 8 ++++++++
src/box/sql/vdbeaux.c | 15 +++++++++++++++
test/sql/full_metadata.result | 38 +++++++++++++++++++++++++++++++++++---
test/sql/full_metadata.test.lua | 7 +++++++
12 files changed, 127 insertions(+), 14 deletions(-)
diff --git a/src/box/execute.c b/src/box/execute.c
index c853991a0..0fe98af3d 100644
--- a/src/box/execute.c
+++ b/src/box/execute.c
@@ -270,7 +270,7 @@ error:
static size_t
metadata_map_sizeof(const char *name, const char *type, const char *coll,
- int nullable, bool is_autoincrement)
+ const char *alias, int nullable, bool is_autoincrement)
{
uint32_t members_count = 2;
size_t map_size = 0;
@@ -279,6 +279,11 @@ metadata_map_sizeof(const char *name, const char *type, const char *coll,
map_size += mp_sizeof_uint(IPROTO_FIELD_COLL);
map_size += mp_sizeof_str(strlen(coll));
}
+ if (alias != NULL) {
+ members_count++;
+ map_size += mp_sizeof_uint(IPROTO_FIELD_ALIAS);
+ map_size += mp_sizeof_str(strlen(alias));
+ }
if (nullable != -1) {
members_count++;
map_size += mp_sizeof_uint(IPROTO_FIELD_IS_NULLABLE);
@@ -323,6 +328,7 @@ sql_get_metadata(struct sql_stmt *stmt, struct obuf *out, int column_count)
const char *coll = sql_column_coll(stmt, i);
const char *name = sql_column_name(stmt, i);
const char *type = sql_column_datatype(stmt, i);
+ const char *alias = sql_column_alias(stmt, i);
int nullable = sql_column_nullable(stmt, i);
bool is_autoincrement = sql_column_is_autoincrement(stmt, i);
/*
@@ -332,15 +338,15 @@ sql_get_metadata(struct sql_stmt *stmt, struct obuf *out, int column_count)
*/
assert(name != NULL);
assert(type != NULL);
- size = metadata_map_sizeof(name, type, coll, nullable,
+ size = metadata_map_sizeof(name, type, coll, alias, nullable,
is_autoincrement);
char *pos = (char *) obuf_alloc(out, size);
if (pos == NULL) {
diag_set(OutOfMemory, size, "obuf_alloc", "pos");
return -1;
}
- uint32_t map_sz = 2 + (coll != NULL) + (nullable != -1) +
- is_autoincrement;
+ uint32_t map_sz = 2 + (coll != NULL) + (alias != NULL) +
+ (nullable != -1) + is_autoincrement;
pos = mp_encode_map(pos, map_sz);
pos = mp_encode_uint(pos, IPROTO_FIELD_NAME);
pos = mp_encode_str(pos, name, strlen(name));
@@ -350,6 +356,10 @@ sql_get_metadata(struct sql_stmt *stmt, struct obuf *out, int column_count)
pos = mp_encode_uint(pos, IPROTO_FIELD_COLL);
pos = mp_encode_str(pos, coll, strlen(coll));
}
+ if (alias != NULL) {
+ pos = mp_encode_uint(pos, IPROTO_FIELD_ALIAS);
+ pos = mp_encode_str(pos, alias, strlen(alias));
+ }
if (nullable != -1) {
pos = mp_encode_uint(pos, IPROTO_FIELD_IS_NULLABLE);
pos = mp_encode_bool(pos, nullable);
diff --git a/src/box/iproto_constants.h b/src/box/iproto_constants.h
index 30d1af4cb..8e50e0cb1 100644
--- a/src/box/iproto_constants.h
+++ b/src/box/iproto_constants.h
@@ -134,6 +134,7 @@ enum iproto_metadata_key {
IPROTO_FIELD_COLL = 2,
IPROTO_FIELD_IS_NULLABLE = 3,
IPROTO_FIELD_IS_AUTOINCREMENT = 4,
+ IPROTO_FIELD_ALIAS = 5,
};
enum iproto_ballot_key {
diff --git a/src/box/lua/execute.c b/src/box/lua/execute.c
index e8e3e2a9f..9055d3a76 100644
--- a/src/box/lua/execute.c
+++ b/src/box/lua/execute.c
@@ -23,10 +23,11 @@ lua_sql_get_metadata(struct sql_stmt *stmt, struct lua_State *L,
const char *coll = sql_column_coll(stmt, i);
const char *name = sql_column_name(stmt, i);
const char *type = sql_column_datatype(stmt, i);
+ const char *alias = sql_column_alias(stmt, i);
int nullable = sql_column_nullable(stmt, i);
bool is_autoincrement = sql_column_is_autoincrement(stmt, i);
- size_t table_sz = 2 + (coll != NULL) + (nullable != -1) +
- is_autoincrement;
+ size_t table_sz = 2 + (coll != NULL) + (alias != NULL) +
+ (nullable != -1) + is_autoincrement ;
lua_createtable(L, 0, table_sz);
/*
* Can not fail, since all column names are
@@ -51,6 +52,10 @@ lua_sql_get_metadata(struct sql_stmt *stmt, struct lua_State *L,
lua_pushboolean(L, true);
lua_setfield(L, -2, "is_autoincrement");
}
+ if (alias != NULL) {
+ lua_pushstring(L, alias);
+ lua_setfield(L, -2, "alias");
+ }
lua_rawseti(L, -2, i + 1);
}
}
diff --git a/src/box/lua/net_box.c b/src/box/lua/net_box.c
index 88ef4ff78..1bfe08f64 100644
--- a/src/box/lua/net_box.c
+++ b/src/box/lua/net_box.c
@@ -655,6 +655,10 @@ decode_metadata_optional(struct lua_State *L, const char **data,
bool is_nullable = mp_decode_bool(data);
lua_pushboolean(L, is_nullable);
lua_setfield(L, -2, "is_nullable");
+ } else if (key == IPROTO_FIELD_ALIAS) {
+ const char *alias = mp_decode_str(data, &len);
+ lua_pushlstring(L, alias, len);
+ lua_setfield(L, -2, "alias");
} else {
assert(key == IPROTO_FIELD_IS_AUTOINCREMENT);
bool autoincrement = mp_decode_bool(data);
@@ -676,7 +680,7 @@ netbox_decode_metadata(struct lua_State *L, const char **data)
lua_createtable(L, count, 0);
for (uint32_t i = 0; i < count; ++i) {
uint32_t map_size = mp_decode_map(data);
- assert(map_size >= 2 && map_size <= 5);
+ assert(map_size >= 2 && map_size <= 6);
uint32_t key = mp_decode_uint(data);
assert(key == IPROTO_FIELD_NAME);
(void) key;
diff --git a/src/box/sql/select.c b/src/box/sql/select.c
index d92da4d8e..c1770e7b4 100644
--- a/src/box/sql/select.c
+++ b/src/box/sql/select.c
@@ -1827,7 +1827,19 @@ generate_column_metadata(struct Parse *pParse, struct SrcList *pTabList,
zCol = space_def->fields[iCol].name;
const char *name = NULL;
if (pEList->a[i].zName != NULL) {
- name = pEList->a[i].zName;
+ if (is_full_meta) {
+ const char *alias = NULL;
+ if (pEList->a[i].zSpan != NULL) {
+ alias = pEList->a[i].zName;
+ name = pEList->a[i].zSpan;
+ } else {
+ alias = pEList->a[i].zName;
+ name = pEList->a[i].zName;
+ }
+ vdbe_metadata_set_col_alias(v, i, alias);
+ } else {
+ name = pEList->a[i].zName;
+ }
} else {
if (!shortNames && !fullNames) {
name = pEList->a[i].zSpan;
@@ -1854,9 +1866,21 @@ generate_column_metadata(struct Parse *pParse, struct SrcList *pTabList,
}
} else {
const char *z = NULL;
- if (pEList->a[i].zName != NULL)
- z = pEList->a[i].zName;
- else if (pEList->a[i].zSpan != NULL)
+ if (pEList->a[i].zName != NULL) {
+ if (is_full_meta ) {
+ const char *alias = NULL;
+ if (pEList->a[i].zSpan != NULL) {
+ alias = pEList->a[i].zName;
+ z = pEList->a[i].zSpan;
+ } else {
+ alias = pEList->a[i].zName;
+ z = pEList->a[i].zName;
+ }
+ vdbe_metadata_set_col_alias(v, i, alias);
+ } else {
+ z = pEList->a[i].zName;
+ }
+ } else if (pEList->a[i].zSpan != NULL)
z = pEList->a[i].zSpan;
else
z = tt_sprintf("column%d", i + 1);
diff --git a/src/box/sql/sqlInt.h b/src/box/sql/sqlInt.h
index e248bc673..b38b66b74 100644
--- a/src/box/sql/sqlInt.h
+++ b/src/box/sql/sqlInt.h
@@ -585,6 +585,9 @@ sql_column_nullable(sql_stmt *stmt, int n);
bool
sql_column_is_autoincrement(sql_stmt *stmt, int n);
+const char *
+sql_column_alias(sql_stmt *stmt, int n);
+
int
sql_initialize(void);
diff --git a/src/box/sql/vdbe.h b/src/box/sql/vdbe.h
index da9a311b8..f35f11241 100644
--- a/src/box/sql/vdbe.h
+++ b/src/box/sql/vdbe.h
@@ -263,6 +263,9 @@ vdbe_metadata_set_col_nullability(struct Vdbe *p, int idx, int nullable);
void
vdbe_metadata_set_col_autoincrement(struct Vdbe *p, int idx);
+int
+vdbe_metadata_set_col_alias(struct Vdbe *p, int idx, const char *alias);
+
void sqlVdbeCountChanges(Vdbe *);
sql *sqlVdbeDb(Vdbe *);
void sqlVdbeSetSql(Vdbe *, const char *z, int n, int);
diff --git a/src/box/sql/vdbeInt.h b/src/box/sql/vdbeInt.h
index d79635b14..eaa40a35e 100644
--- a/src/box/sql/vdbeInt.h
+++ b/src/box/sql/vdbeInt.h
@@ -350,6 +350,7 @@ struct sql_column_metadata {
char *name;
char *type;
char *collation;
+ char *alias;
/**
* -1 is for any member of result set except for pure
* columns: all other expressions are nullable by default.
diff --git a/src/box/sql/vdbeapi.c b/src/box/sql/vdbeapi.c
index 5b423c9df..47cd068ff 100644
--- a/src/box/sql/vdbeapi.c
+++ b/src/box/sql/vdbeapi.c
@@ -769,6 +769,14 @@ sql_column_is_autoincrement(sql_stmt *stmt, int n)
return p->metadata[n].is_actoincrement;
}
+const char *
+sql_column_alias(sql_stmt *stmt, int n)
+{
+ struct Vdbe *p = (struct Vdbe *) stmt;
+ assert(n < sql_column_count(stmt) && n >= 0);
+ return p->metadata[n].alias;
+}
+
/******************************* sql_bind_ **************************
*
* Routines used to attach values to wildcards in a compiled SQL statement.
diff --git a/src/box/sql/vdbeaux.c b/src/box/sql/vdbeaux.c
index e3672097c..625464902 100644
--- a/src/box/sql/vdbeaux.c
+++ b/src/box/sql/vdbeaux.c
@@ -1835,6 +1835,7 @@ vdbe_metadata_delete(struct Vdbe *v)
free(v->metadata[i].name);
free(v->metadata[i].type);
free(v->metadata[i].collation);
+ free(v->metadata[i].alias);
}
free(v->metadata);
}
@@ -1918,6 +1919,20 @@ vdbe_metadata_set_col_autoincrement(struct Vdbe *p, int idx)
p->metadata[idx].is_actoincrement = 1;
}
+int
+vdbe_metadata_set_col_alias(struct Vdbe *p, int idx, const char *alias)
+{
+ assert(idx < p->nResColumn);
+ if (p->metadata[idx].alias != NULL)
+ free((void *)p->metadata[idx].alias);
+ p->metadata[idx].alias = strdup(alias);
+ if (p->metadata[idx].alias == NULL) {
+ diag_set(OutOfMemory, strlen(alias) + 1, "strdup", "alias");
+ return -1;
+ }
+ return 0;
+}
+
/*
* This routine checks that the sql.nVdbeActive count variable
* matches the number of vdbe's in the list sql.pVdbe that are
diff --git a/test/sql/full_metadata.result b/test/sql/full_metadata.result
index 7c2982682..8f0bced36 100644
--- a/test/sql/full_metadata.result
+++ b/test/sql/full_metadata.result
@@ -103,14 +103,17 @@ execute("SELECT id, a, c FROM t;")
execute("SELECT * FROM t;")
| ---
| - metadata:
- | - type: integer
+ | - alias: ID
+ | type: integer
| is_autoincrement: true
| name: ID
| is_nullable: false
| - type: integer
- | name: A
| is_nullable: false
- | - type: string
+ | name: A
+ | alias: A
+ | - alias: C
+ | type: string
| is_nullable: true
| name: C
| collation: unicode_ci
@@ -118,6 +121,35 @@ execute("SELECT * FROM t;")
| - [1, 1, 'aSd']
| ...
+-- Alias is always set in extended metadata. If column label in
+-- form of AS clause is set, then this alias is presented in
+-- metadata. Otherwise, alias is just the same as name.
+--
+execute("SELECT 1 AS x;")
+ | ---
+ | - metadata:
+ | - type: integer
+ | name: '1'
+ | alias: X
+ | rows:
+ | - [1]
+ | ...
+execute("SELECT a AS a_label, c AS c_label FROM t;")
+ | ---
+ | - metadata:
+ | - type: integer
+ | is_nullable: false
+ | name: a
+ | alias: A_LABEL
+ | - alias: C_LABEL
+ | type: string
+ | is_nullable: true
+ | name: c
+ | collation: unicode_ci
+ | rows:
+ | - [1, 'aSd']
+ | ...
+
execute("PRAGMA full_metadata = false;")
| ---
| - row_count: 0
diff --git a/test/sql/full_metadata.test.lua b/test/sql/full_metadata.test.lua
index e6bfa1eaf..533fa90c7 100644
--- a/test/sql/full_metadata.test.lua
+++ b/test/sql/full_metadata.test.lua
@@ -35,6 +35,13 @@ execute("SELECT c COLLATE \"unicode\" FROM t;")
execute("SELECT id, a, c FROM t;")
execute("SELECT * FROM t;")
+-- Alias is always set in extended metadata. If column label in
+-- form of AS clause is set, then this alias is presented in
+-- metadata. Otherwise, alias is just the same as name.
+--
+execute("SELECT 1 AS x;")
+execute("SELECT a AS a_label, c AS c_label FROM t;")
+
execute("PRAGMA full_metadata = false;")
test_run:cmd("setopt delimiter ';'")
--
2.15.1
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