TYPE

TYPE — 定义一种新数据类型

大纲

TYPE type_name IS ctype

描述

TYPE命令定义一个新的 C 类型。它等效于把一个typedef放在声明节中。

只有使用选项-c运行ecpg时才能识别这个命令。

参数

例子

EXEC SQL TYPE customer IS
 struct
 {
 varchar name[50];
 int phone;
 };
EXEC SQL TYPE cust_ind IS
 struct ind
 {
 short name_ind;
 short phone_ind;
 };
EXEC SQL TYPE c IS char reference;
EXEC SQL TYPE ind IS union { int integer; short smallint; };
EXEC SQL TYPE intarray IS int[AMOUNT];
EXEC SQL TYPE str IS varchar[BUFFERSIZ];
EXEC SQL TYPE string IS char[11];

这里是一个使用EXEC SQL TYPE的例子程序:

EXEC SQL WHENEVER SQLERROR SQLPRINT;
EXEC SQL TYPE tt IS
 struct
 {
 varchar v[256];
 int i;
 };
EXEC SQL TYPE tt_ind IS
 struct ind {
 short v_ind;
 short i_ind;
 };
int
main(void)
{
EXEC SQL BEGIN DECLARE SECTION;
 tt t;
 tt_ind t_ind;
EXEC SQL END DECLARE SECTION;
 EXEC SQL CONNECT TO testdb AS con1;
 EXEC SQL SELECT current_database(), 256 INTO :t:t_ind LIMIT 1;
 printf("t.v = %s\n", t.v.arr);
 printf("t.i = %d\n", t.i);
 printf("t_ind.v_ind = %d\n", t_ind.v_ind);
 printf("t_ind.i_ind = %d\n", t_ind.i_ind);
 EXEC SQL DISCONNECT con1;
 return 0;
}

这个程序的输出看起来像:

t.v = testdb
t.i = 256
t_ind.v_ind = 0
t_ind.i_ind = 0

兼容性

TYPE命令是一种 PostgreSQL 扩展。