Basic Operations in TDSQL-C (MySQL Edition)

Querying version

Method 1:

MySQL [(none)]> SELECT CYNOS_VERSION();
+------------------------+
| CYNOS_VERSION() |
+------------------------+
| 5.7.mysql_cynos.1.3.10 |
+------------------------+
1 row in set (0.00 sec)

Method 2:

MySQL [(none)]> SELECT @@CYNOS_VERSION;
+------------------------+
| @@CYNOS_VERSION |
+------------------------+
| 5.7.mysql_cynos.1.3.10 |
+------------------------+
1 row in set (0.00 sec)

Method 3:

MySQL [(none)]> SHOW VARIABLES LIKE 'CYNOS_VERSION'; 
+---------------+------------------------+
| Variable_name | Value |
+---------------+------------------------+
| cynos_version | 5.7.mysql_cynos.1.3.10 |
+---------------+------------------------+
1 row in set (0.01 sec)

Basic Operations in TDSQL-C (PostgreSQL Edition)

Querying version

postgres=# select cynosdb_version(); cynosdb_version
————————
CynosDB 1.0
(1 row)

Creating table

postgres=# create table x(x1 int, x2 int);
CREATE TABLE
postgres=# insert into x values(1, 2);
INSERT 0 1
postgres=# update x set x1 = 1;
UPDATE 1

Creating view

postgres=# create view v_x as select * from x;
CREATE VIEW
postgres=# select * from v_x;
 x1 | x2
——+——
 1 |  2
(1 row)

Querying table

postgres=# select * from x;

x1 | x2
——+——
 1 |  2
(1 row)

System table

TDSQL-C supports PostgreSQL 10 system tables, such as pg_class and pg_proc.

GUC parameters

TDSQL-C is compatible with the GUC parameters of PostgreSQL 10. You can use the SHOW or SET command to display or set GUC parameters.

Index

TDSQL-C supports multiple indexes, such as B-tree, Hash, GiST, SP-GiST, GIN, and BRIN. The default index created by CREATE INDEX is B-tree index.

Multi-Column and single-column indexes

postgres=# CREATE TABLE test2 (
postgres(#   major int,
postgres(#   minor int,
postgres(#   name varchar
postgres(# );
CREATE TABLE

Supporting multi-column index

postgres=# CREATE INDEX test2_mm_idx ON test2 (major, minor);
CREATE INDEX

Supporting single-column index

postgres=# CREATE INDEX test2_mm ON test2 (name);
CREATE INDEX

Expression index

TDSQL-C is compatible with PostgreSQL 10 and supports expression indexes.

postgres=# CREATE INDEX test2_expr ON test2 ((major + minor));
CREATE INDEX