我已经在postgreSQL中创建了一个表。我想查看用于创建表的SQL语句，但无法找出它。
如何通过命令行或SQL语句获得Postgres中现有表的创建表SQL语句?
当前回答
我能想到的最简单的方法是安装pgAdmin 3(在这里找到)，并用它来查看数据库。它将自动生成一个查询，该查询将创建所讨论的表。
其他回答
从linux命令行在postgresql中为一个表生成create table语句:
为演示创建一个表:
CREATE TABLE your_table(
thekey integer NOT NULL,
ticker character varying(10) NOT NULL,
date_val date,
open_val numeric(10,4) NOT NULL
);
Pg_dump手动，可以输出表创建PSQL语句:
pg_dump -U your_user your_database -t your_table --schema-only
打印:
-- pre-requisite database and table configuration omitted
CREATE TABLE your_table (
thekey integer NOT NULL,
ticker character varying(10) NOT NULL,
date_val date,
open_val numeric(10,4) NOT NULL
);
-- post-requisite database and table configuration omitted
解释:
Pg_dump帮助我们获得关于数据库本身的信息。-U代表用户名。我的pgadmin用户没有设置密码，所以我不需要输入密码。-t选项表示指定一个表。——schema-only表示只打印关于表的数据，而不是表中的数据。
pg_dump是优秀的C代码，它试图很好地处理不断发展的sql标准，并处理在postgresql的查询语言和它在磁盘上的表示之间产生的成千上万个细节。如果你想卷自己的“psql磁盘创建语句”的安排，你是龙:https://doxygen.postgresql.org/pg__dump_8c_source.html
另一个绕过pg_dump的选项是在创建表时保存表创建SQL语句。把它放在安全的地方，需要的时候拿来。
或者使用SQL从postgresql中获取表名、列名和数据类型信息:
CREATE TABLE your_table( thekey integer NOT NULL,
ticker character varying(10) NOT NULL,
date_val date,
open_val numeric(10,4) NOT NULL
);
SELECT table_name, column_name, data_type
FROM information_schema.columns
WHERE table_name = 'your_table';
打印:
┌────────────┬─────────────┬───────────────────┐
│ table_name │ column_name │ data_type │
├────────────┼─────────────┼───────────────────┤
│ your_table │ thekey │ integer │
│ your_table │ ticker │ character varying │
│ your_table │ date_val │ date │
│ your_table │ open_val │ numeric │
└────────────┴─────────────┴───────────────────┘
另一个简单的选择是使用[HeidiSQL client][1]作为PostgreSQL数据库。
如何进入列出所有数据库和表的数据库选项卡。
单击想要查看DDL/创建特定表的语句的任何表/视图。
现在这个客户端为你在右边窗口的桌子上做以下工作:
第一个窗口将用于表中的数据
第二个是SQL主机信息
第三是数据库级别的信息，比如哪些表，大小是多少
第四，我们更关心的表/视图信息选项卡将有create table语句随时为您提供。
我不能在快照中显示你在处理机密数据，自己试试，让我知道如果你们发现了任何问题。
甚至根据@vkkeeper的响应进行了更多的修改。增加了从特定模式查询表的可能性。
CREATE OR REPLACE FUNCTION public.describe_table(p_schema_name character varying, p_table_name character varying)
RETURNS SETOF text AS
$BODY$
DECLARE
v_table_ddl text;
column_record record;
table_rec record;
constraint_rec record;
firstrec boolean;
BEGIN
FOR table_rec IN
SELECT c.relname, c.oid FROM pg_catalog.pg_class c
LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
WHERE relkind = 'r'
AND n.nspname = p_schema_name
AND relname~ ('^('||p_table_name||')$')
ORDER BY c.relname
LOOP
FOR column_record IN
SELECT
b.nspname as schema_name,
b.relname as table_name,
a.attname as column_name,
pg_catalog.format_type(a.atttypid, a.atttypmod) as column_type,
CASE WHEN
(SELECT substring(pg_catalog.pg_get_expr(d.adbin, d.adrelid) for 128)
FROM pg_catalog.pg_attrdef d
WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum AND a.atthasdef) IS NOT NULL THEN
'DEFAULT '|| (SELECT substring(pg_catalog.pg_get_expr(d.adbin, d.adrelid) for 128)
FROM pg_catalog.pg_attrdef d
WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum AND a.atthasdef)
ELSE
''
END as column_default_value,
CASE WHEN a.attnotnull = true THEN
'NOT NULL'
ELSE
'NULL'
END as column_not_null,
a.attnum as attnum,
e.max_attnum as max_attnum
FROM
pg_catalog.pg_attribute a
INNER JOIN
(SELECT c.oid,
n.nspname,
c.relname
FROM pg_catalog.pg_class c
LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
WHERE c.oid = table_rec.oid
ORDER BY 2, 3) b
ON a.attrelid = b.oid
INNER JOIN
(SELECT
a.attrelid,
max(a.attnum) as max_attnum
FROM pg_catalog.pg_attribute a
WHERE a.attnum > 0
AND NOT a.attisdropped
GROUP BY a.attrelid) e
ON a.attrelid=e.attrelid
WHERE a.attnum > 0
AND NOT a.attisdropped
ORDER BY a.attnum
LOOP
IF column_record.attnum = 1 THEN
v_table_ddl:='CREATE TABLE '||column_record.schema_name||'.'||column_record.table_name||' (';
ELSE
v_table_ddl:=v_table_ddl||',';
END IF;
IF column_record.attnum <= column_record.max_attnum THEN
v_table_ddl:=v_table_ddl||chr(10)||
' '||column_record.column_name||' '||column_record.column_type||' '||column_record.column_default_value||' '||column_record.column_not_null;
END IF;
END LOOP;
firstrec := TRUE;
FOR constraint_rec IN
SELECT conname, pg_get_constraintdef(c.oid) as constrainddef
FROM pg_constraint c
WHERE conrelid=(
SELECT attrelid FROM pg_attribute
WHERE attrelid = (
SELECT oid FROM pg_class WHERE relname = table_rec.relname
AND relnamespace = (SELECT ns.oid FROM pg_namespace ns WHERE ns.nspname = p_schema_name)
) AND attname='tableoid'
)
LOOP
v_table_ddl:=v_table_ddl||','||chr(10);
v_table_ddl:=v_table_ddl||'CONSTRAINT '||constraint_rec.conname;
v_table_ddl:=v_table_ddl||chr(10)||' '||constraint_rec.constrainddef;
firstrec := FALSE;
END LOOP;
v_table_ddl:=v_table_ddl||');';
RETURN NEXT v_table_ddl;
END LOOP;
END;
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
(注意-此解决方案不适用于PostgreSQL v12+)
我的解决方案是使用psql和-E选项登录postgres db，如下所示:
psql -E -U username -d database
在psql中，运行以下命令查看postgres用来生成的sql 描述表语句:
-- List all tables in the schema (my example schema name is public)
\dt public.*
-- Choose a table name from above
-- For create table of one public.tablename
\d+ public.tablename
基于运行这些描述命令后返回的sql，我能够把它们放在一起 下面是PLPGSQL函数:
CREATE OR REPLACE FUNCTION generate_create_table_statement(p_table_name varchar)
RETURNS text AS
$BODY$
DECLARE
v_table_ddl text;
column_record record;
BEGIN
FOR column_record IN
SELECT
b.nspname as schema_name,
b.relname as table_name,
a.attname as column_name,
pg_catalog.format_type(a.atttypid, a.atttypmod) as column_type,
CASE WHEN
(SELECT substring(pg_catalog.pg_get_expr(d.adbin, d.adrelid) for 128)
FROM pg_catalog.pg_attrdef d
WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum AND a.atthasdef) IS NOT NULL THEN
'DEFAULT '|| (SELECT substring(pg_catalog.pg_get_expr(d.adbin, d.adrelid) for 128)
FROM pg_catalog.pg_attrdef d
WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum AND a.atthasdef)
ELSE
''
END as column_default_value,
CASE WHEN a.attnotnull = true THEN
'NOT NULL'
ELSE
'NULL'
END as column_not_null,
a.attnum as attnum,
e.max_attnum as max_attnum
FROM
pg_catalog.pg_attribute a
INNER JOIN
(SELECT c.oid,
n.nspname,
c.relname
FROM pg_catalog.pg_class c
LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
WHERE c.relname ~ ('^('||p_table_name||')$')
AND pg_catalog.pg_table_is_visible(c.oid)
ORDER BY 2, 3) b
ON a.attrelid = b.oid
INNER JOIN
(SELECT
a.attrelid,
max(a.attnum) as max_attnum
FROM pg_catalog.pg_attribute a
WHERE a.attnum > 0
AND NOT a.attisdropped
GROUP BY a.attrelid) e
ON a.attrelid=e.attrelid
WHERE a.attnum > 0
AND NOT a.attisdropped
ORDER BY a.attnum
LOOP
IF column_record.attnum = 1 THEN
v_table_ddl:='CREATE TABLE '||column_record.schema_name||'.'||column_record.table_name||' (';
ELSE
v_table_ddl:=v_table_ddl||',';
END IF;
IF column_record.attnum <= column_record.max_attnum THEN
v_table_ddl:=v_table_ddl||chr(10)||
' '||column_record.column_name||' '||column_record.column_type||' '||column_record.column_default_value||' '||column_record.column_not_null;
END IF;
END LOOP;
v_table_ddl:=v_table_ddl||');';
RETURN v_table_ddl;
END;
$BODY$
LANGUAGE 'plpgsql' COST 100.0 SECURITY INVOKER;
下面是函数用法:
SELECT generate_create_table_statement('tablename');
下面是drop语句，如果你不想让这个函数永久保存:
DROP FUNCTION generate_create_table_statement(p_table_name varchar);
一个简单的解决方案，在纯SQL。 您可以将其扩展到您想要显示的更多属性。
with c as (
SELECT table_name, ordinal_position,
column_name|| ' ' || data_type col
, row_number() over (partition by table_name order by ordinal_position asc) rn
, count(*) over (partition by table_name) cnt
FROM information_schema.columns
WHERE table_name in ('pg_index', 'pg_tables')
order by table_name, ordinal_position
)
select case when rn = 1 then 'create table ' || table_name || '(' else '' end
|| col
|| case when rn < cnt then ',' else '); ' end
from c
order by table_name, rn asc;
输出:
create table pg_index(indexrelid oid,
indrelid oid,
indnatts smallint,
indisunique boolean,
indisprimary boolean,
indisexclusion boolean,
indimmediate boolean,
indisclustered boolean,
indisvalid boolean,
indcheckxmin boolean,
indisready boolean,
indislive boolean,
indisreplident boolean,
indkey ARRAY,
indcollation ARRAY,
indclass ARRAY,
indoption ARRAY,
indexprs pg_node_tree,
indpred pg_node_tree);
create table pg_tables(schemaname name,
tablename name,
tableowner name,
tablespace name,
hasindexes boolean,
hasrules boolean,
hastriggers boolean,
rowsecurity boolean);
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