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

下面是一条语句,它将为指定模式(包括约束)中的单个表生成DDL。

SELECT 'CREATE TABLE ' || pn.nspname || '.' || pc.relname || E'(\n' ||
   string_agg(pa.attname || ' ' || pg_catalog.format_type(pa.atttypid, pa.atttypmod) || coalesce(' DEFAULT ' || (
                                                                                                               SELECT pg_catalog.pg_get_expr(d.adbin, d.adrelid)
                                                                                                               FROM pg_catalog.pg_attrdef d
                                                                                                               WHERE d.adrelid = pa.attrelid
                                                                                                                 AND d.adnum = pa.attnum
                                                                                                                 AND pa.atthasdef
                                                                                                               ),
                                                                                                 '') || ' ' ||
              CASE pa.attnotnull
                  WHEN TRUE THEN 'NOT NULL'
                  ELSE 'NULL'
              END, E',\n') ||
   coalesce((SELECT E',\n' || string_agg('CONSTRAINT ' || pc1.conname || ' ' || pg_get_constraintdef(pc1.oid), E',\n' ORDER BY pc1.conindid)
            FROM pg_constraint pc1
            WHERE pc1.conrelid = pa.attrelid), '') ||
   E');'
FROM pg_catalog.pg_attribute pa
JOIN pg_catalog.pg_class pc
    ON pc.oid = pa.attrelid
    AND pc.relname = 'table_name'
JOIN pg_catalog.pg_namespace pn
    ON pn.oid = pc.relnamespace
    AND pn.nspname = 'schema_name'
WHERE pa.attnum > 0
    AND NOT pa.attisdropped
GROUP BY pn.nspname, pc.relname, pa.attrelid;

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           │ 
└────────────┴─────────────┴───────────────────┘ 

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);

如果您不想创建函数,而只想让查询创建一个基本的表结构,这里有一个解决方案。

select 'CREATE TABLE ' || table_name ||'(' ||STRING_AGG (
    column_name || ' ' || data_type ,
        ','
       ORDER BY
        table_name,
        ordinal_position
    ) ||');'
    from 
information_schema.columns 
where table_schema = 'public'
group by 
table_name

这是对我有用的变化:

pg_dump -U user_viktor -h localhost unit_test_database -t floorplanpreferences_table——schema-only

此外,如果你正在使用模式,你当然也需要指定:

pg_dump -U user_viktor -h localhost unit_test_database -t "949766e0-e81e-11e3-b325-1cc1de32fcb6"。floorplanpreferences_table——模式

您将得到一个输出,可以用来再次创建表,只需在psql中运行该输出。

与前面提到的其他答案一样,没有内置函数可以做到这一点。

下面是一个函数,它试图获取复制表或比较ddl中部署和检查所需的所有信息。

这个函数输出:

列(w/ precision, null/not-null,默认值) 约束 索引


CREATE OR REPLACE FUNCTION public.show_create_table(
  in_schema_name varchar,
  in_table_name varchar
)
RETURNS text
LANGUAGE plpgsql VOLATILE
AS
$$
  DECLARE
    -- the ddl we're building
    v_table_ddl text;

    -- data about the target table
    v_table_oid int;

    -- records for looping
    v_column_record record;
    v_constraint_record record;
    v_index_record record;
  BEGIN
    -- grab the oid of the table; https://www.postgresql.org/docs/8.3/catalog-pg-class.html
    SELECT c.oid INTO v_table_oid
    FROM pg_catalog.pg_class c
    LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
    WHERE 1=1
      AND c.relkind = 'r' -- r = ordinary table; https://www.postgresql.org/docs/9.3/catalog-pg-class.html
      AND c.relname = in_table_name -- the table name
      AND n.nspname = in_schema_name; -- the schema

    -- throw an error if table was not found
    IF (v_table_oid IS NULL) THEN
      RAISE EXCEPTION 'table does not exist';
    END IF;

    -- start the create definition
    v_table_ddl := 'CREATE TABLE ' || in_schema_name || '.' || in_table_name || ' (' || E'\n';

    -- define all of the columns in the table; https://stackoverflow.com/a/8153081/3068233
    FOR v_column_record IN
      SELECT
        c.column_name,
        c.data_type,
        c.character_maximum_length,
        c.is_nullable,
        c.column_default
      FROM information_schema.columns c
      WHERE (table_schema, table_name) = (in_schema_name, in_table_name)
      ORDER BY ordinal_position
    LOOP
      v_table_ddl := v_table_ddl || '  ' -- note: two char spacer to start, to indent the column
        || v_column_record.column_name || ' '
        || v_column_record.data_type || CASE WHEN v_column_record.character_maximum_length IS NOT NULL THEN ('(' || v_column_record.character_maximum_length || ')') ELSE '' END || ' '
        || CASE WHEN v_column_record.is_nullable = 'NO' THEN 'NOT NULL' ELSE 'NULL' END
        || CASE WHEN v_column_record.column_default IS NOT null THEN (' DEFAULT ' || v_column_record.column_default) ELSE '' END
        || ',' || E'\n';
    END LOOP;

    -- define all the constraints in the; https://www.postgresql.org/docs/9.1/catalog-pg-constraint.html && https://dba.stackexchange.com/a/214877/75296
    FOR v_constraint_record IN
      SELECT
        con.conname as constraint_name,
        con.contype as constraint_type,
        CASE
          WHEN con.contype = 'p' THEN 1 -- primary key constraint
          WHEN con.contype = 'u' THEN 2 -- unique constraint
          WHEN con.contype = 'f' THEN 3 -- foreign key constraint
          WHEN con.contype = 'c' THEN 4
          ELSE 5
        END as type_rank,
        pg_get_constraintdef(con.oid) as constraint_definition
      FROM pg_catalog.pg_constraint con
      JOIN pg_catalog.pg_class rel ON rel.oid = con.conrelid
      JOIN pg_catalog.pg_namespace nsp ON nsp.oid = connamespace
      WHERE nsp.nspname = in_schema_name
      AND rel.relname = in_table_name
      ORDER BY type_rank
    LOOP
      v_table_ddl := v_table_ddl || '  ' -- note: two char spacer to start, to indent the column
        || 'CONSTRAINT' || ' '
        || v_constraint_record.constraint_name || ' '
        || v_constraint_record.constraint_definition
        || ',' || E'\n';
    END LOOP;

    -- drop the last comma before ending the create statement
    v_table_ddl = substr(v_table_ddl, 0, length(v_table_ddl) - 1) || E'\n';

    -- end the create definition
    v_table_ddl := v_table_ddl || ');' || E'\n';

    -- suffix create statement with all of the indexes on the table
    FOR v_index_record IN
      SELECT indexdef
      FROM pg_indexes
      WHERE (schemaname, tablename) = (in_schema_name, in_table_name)
    LOOP
      v_table_ddl := v_table_ddl
        || v_index_record.indexdef
        || ';' || E'\n';
    END LOOP;

    -- return the ddl
    RETURN v_table_ddl;
  END;
$$;

例子

SELECT * FROM public.show_create_table('public', 'example_table');

生产

CREATE TABLE public.example_table (
  id bigint NOT NULL DEFAULT nextval('test_tb_for_show_create_on_id_seq'::regclass),
  name character varying(150) NULL,
  level character varying(50) NULL,
  description text NOT NULL DEFAULT 'hello there!'::text,
  CONSTRAINT test_tb_for_show_create_on_pkey PRIMARY KEY (id),
  CONSTRAINT test_tb_for_show_create_on_level_check CHECK (((level)::text = ANY ((ARRAY['info'::character varying, 'warn'::character varying, 'error'::character varying])::text[])))
);
CREATE UNIQUE INDEX test_tb_for_show_create_on_pkey ON public.test_tb_for_show_create_on USING btree (id);