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

这是一个有一些编辑的查询,

select 'CREATE TABLE ' || a.attrelid::regclass::text || '(' ||
string_agg(a.attname || ' ' || pg_catalog.format_type(a.atttypid, 
a.atttypmod)||
        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
||
        CASE WHEN a.attnotnull = true THEN 
            ' NOT NULL'
        ELSE
            '' END,E'\n,') || ');' 
FROM pg_catalog.pg_attribute a join pg_class on a.attrelid=pg_class.oid
WHERE a.attrelid::regclass::varchar =  
'TABLENAME_with_or_without_schema'
AND a.attnum > 0 AND NOT a.attisdropped  and pg_class.relkind='r'
group by a.attrelid;

其他回答

(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);

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);

使用它并在ddl中获得输出。出文件

~/bin/pg_dump -p 30000 -d <db_name> -U <db_user> --schema=<schema_name> -t <table_name> --schema-only >> /tmp/ddl.out

因此这将在路径:/tmp/ DDL .out中生成DDL

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。

pg_dump -h XXXXXXXXXXX.us-west-1.rds.amazonaws.com -U anyuser -t tablename -s