2017-04-28 6:08 GMT+02:00 Pavel Stehule <pavel.steh...@gmail.com>:
> Hi
>
> Sometimes I have to solve the result types of some query. It is invisible
> in psql. You have to materialize table or you have to create view. Now,
> when we can enhance \g command, we can introduce query describing
>
> some like
>
> select a, b from foo
> \gdesc
>
> | type | length | collation | ....
> ------------------------------------------------
> a | varchar | 30 |
> b | numeric | 20 |
>
>
here is the patch. It is based on PQdescribePrepared result.
postgres=# select * from pg_proc \gdesc
┌─────────────────┬──────────────┐
│ Name │ Type │
╞═════════════════╪══════════════╡
│ proname │ name │
│ pronamespace │ oid │
│ proowner │ oid │
│ prolang │ oid │
│ procost │ real │
│ prorows │ real │
│ provariadic │ oid │
│ protransform │ regproc │
│ proisagg │ boolean │
│ proiswindow │ boolean │
│ prosecdef │ boolean │
│ proleakproof │ boolean │
│ proisstrict │ boolean │
│ proretset │ boolean │
│ provolatile │ "char" │
│ proparallel │ "char" │
│ pronargs │ smallint │
│ pronargdefaults │ smallint │
│ prorettype │ oid │
│ proargtypes │ oidvector │
│ proallargtypes │ oid[] │
│ proargmodes │ "char"[] │
│ proargnames │ text[] │
│ proargdefaults │ pg_node_tree │
│ protrftypes │ oid[] │
│ prosrc │ text │
│ probin │ text │
│ proconfig │ text[] │
│ proacl │ aclitem[] │
└─────────────────┴──────────────┘
(29 rows)
> What do you think about this idea?
>
> Regards
>
> Pavel
>
diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 3b86612..03cba87 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1957,6 +1957,16 @@ Tue Oct 26 21:40:57 CEST 1999
<varlistentry>
+ <term><literal>\gdesc</literal></term>
+ <listitem>
+ <para>
+ Create unnamed prepared statement from current buffer and get and
+ show description of this prepared statement.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
<term><literal>\gexec</literal></term>
<listitem>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 859ded7..282e2e5 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -88,6 +88,7 @@ static backslashResult exec_command_errverbose(PsqlScanState scan_state, bool ac
static backslashResult exec_command_f(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_g(PsqlScanState scan_state, bool active_branch,
const char *cmd);
+static backslashResult exec_command_gdesc(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_gexec(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_gset(PsqlScanState scan_state, bool active_branch);
static backslashResult exec_command_help(PsqlScanState scan_state, bool active_branch);
@@ -337,6 +338,8 @@ exec_command(const char *cmd,
status = exec_command_f(scan_state, active_branch);
else if (strcmp(cmd, "g") == 0 || strcmp(cmd, "gx") == 0)
status = exec_command_g(scan_state, active_branch, cmd);
+ else if (strcmp(cmd, "gdesc") == 0)
+ status = exec_command_gdesc(scan_state, active_branch);
else if (strcmp(cmd, "gexec") == 0)
status = exec_command_gexec(scan_state, active_branch);
else if (strcmp(cmd, "gset") == 0)
@@ -1328,6 +1331,25 @@ exec_command_g(PsqlScanState scan_state, bool active_branch, const char *cmd)
}
/*
+ * \gdesc -- describe query result
+ */
+static backslashResult
+exec_command_gdesc(PsqlScanState scan_state, bool active_branch)
+{
+ backslashResult status = PSQL_CMD_SKIP_LINE;
+
+ if (active_branch)
+ {
+ pset.gdesc_flag = true;
+ status = PSQL_CMD_SEND;
+ }
+ else
+ ignore_slash_filepipe(scan_state);
+
+ return status;
+}
+
+/*
* \gexec -- send query and execute each field of result
*/
static backslashResult
diff --git a/src/bin/psql/common.c b/src/bin/psql/common.c
index a2f1259..8a16744 100644
--- a/src/bin/psql/common.c
+++ b/src/bin/psql/common.c
@@ -1323,7 +1323,62 @@ SendQuery(const char *query)
}
}
- if (pset.fetch_count <= 0 || pset.gexec_flag ||
+ if (pset.gdesc_flag)
+ {
+ results = PQprepare(pset.db, "", query, 0, NULL);
+ OK = ProcessResult(&results);
+
+ if (OK && results)
+ {
+ results = PQdescribePrepared(pset.db, "");
+ OK = ProcessResult(&results);
+
+ if (OK && results)
+ {
+ PQExpBufferData buf;
+ int i;
+
+ initPQExpBuffer(&buf);
+ printfPQExpBuffer(&buf,
+ "SELECT name AS \"Name\", pg_catalog.format_type(tp, tpm) AS \"Type\" FROM\n"
+ " (VALUES ");
+
+ for(i = 0; i< PQnfields(results); i++)
+ {
+ char *name;
+ char *escname;
+ size_t name_length;
+
+ if (i > 0)
+ appendPQExpBufferStr(&buf, ",");
+
+ name = PQfname(results, i);
+ name_length = strlen(name);
+ escname = pg_malloc(name_length * 2 + 1);
+ PQescapeStringConn(pset.db, escname, name, name_length, NULL);
+
+ appendPQExpBuffer(&buf, "('%s', %d, %d)",
+ escname, PQftype(results,i), PQfmod(results,i));
+ free(escname);
+ }
+
+ appendPQExpBuffer(&buf,") s (name, tp, tpm)");
+ PQclear(results);
+
+ results = PQexec(pset.db, buf.data);
+ OK = ProcessResult(&results);
+
+ if (OK && results)
+ OK = PrintQueryResults(results);
+
+ termPQExpBuffer(&buf);
+ }
+ }
+
+ ResetCancelConn();
+ results = NULL; /* PQclear(NULL) does nothing */
+ }
+ else if (pset.fetch_count <= 0 || pset.gexec_flag ||
pset.crosstab_flag || !is_select_command(query))
{
/* Default fetch-it-all-and-print mode */
@@ -1478,6 +1533,9 @@ sendquery_cleanup:
pset.ctv_args[i] = NULL;
}
+ /* reset \gdesc trigger */
+ pset.gdesc_flag = false;
+
return OK;
}
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index ac43522..6595df4 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -167,12 +167,13 @@ slashUsage(unsigned short int pager)
* Use "psql --help=commands | wc" to count correctly. It's okay to count
* the USE_READLINE line even in builds without that.
*/
- output = PageOutput(122, pager ? &(pset.popt.topt) : NULL);
+ output = PageOutput(123, pager ? &(pset.popt.topt) : NULL);
fprintf(output, _("General\n"));
fprintf(output, _(" \\copyright show PostgreSQL usage and distribution terms\n"));
fprintf(output, _(" \\errverbose show most recent error message at maximum verbosity\n"));
fprintf(output, _(" \\g [FILE] or ; execute query (and send results to file or |pipe)\n"));
+ fprintf(output, _(" \\gdesc describe result of query\n"));
fprintf(output, _(" \\gx [FILE] as \\g, but forces expanded output mode\n"));
fprintf(output, _(" \\gexec execute query, then execute each value in its result\n"));
fprintf(output, _(" \\gset [PREFIX] execute query and store results in psql variables\n"));
diff --git a/src/bin/psql/settings.h b/src/bin/psql/settings.h
index 70ff181..a175912 100644
--- a/src/bin/psql/settings.h
+++ b/src/bin/psql/settings.h
@@ -95,6 +95,7 @@ typedef struct _psqlSettings
char *gset_prefix; /* one-shot prefix argument for \gset */
bool gexec_flag; /* one-shot flag to execute query's results */
bool crosstab_flag; /* one-shot request to crosstab results */
+ bool gdesc_flag; /* one-shot request to describe query */
char *ctv_args[4]; /* \crosstabview arguments */
bool notty; /* stdin or stdout is not a tty (as determined
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index e2a3351..cf591c5 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1410,7 +1410,7 @@ psql_completion(const char *text, int start, int end)
"\\dm", "\\dn", "\\do", "\\dO", "\\dp", "\\drds", "\\ds", "\\dS",
"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dy",
"\\e", "\\echo", "\\ef", "\\encoding", "\\errverbose", "\\ev",
- "\\f", "\\g", "\\gexec", "\\gset", "\\gx", "\\h", "\\help", "\\H",
+ "\\f", "\\g", "\\gdesc", "\\gexec", "\\gset", "\\gx", "\\h", "\\help", "\\H",
"\\i", "\\ir", "\\l", "\\lo_import", "\\lo_export", "\\lo_list",
"\\lo_unlink", "\\o", "\\p", "\\password", "\\prompt", "\\pset", "\\q",
"\\qecho", "\\r", "\\s", "\\set", "\\setenv", "\\sf", "\\sv", "\\t",
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