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I am trying to insert 2 separate arrays into multiple records on 1 SQL Insert Command. I have done the foreach command but it will only accept 1 of the arrays. I have tried doing nested foreach statements but that just puts in way to many records. Below is the code I have so far. I am not posting my connection code to my DB but I ensure you that it connecting to the DB.
$array1 = #(1,2,3)
$array2 = #(a,b,c)
foreach ($file in $array1)
{
$SqlQuery.Append("USE $SQLDBName;")
$SqlQuery.Append("INSERT INTO tbl_File(Column1, Column2, Column3)")
$SqlQuery.Append("VALUES('Dummy Data', '$file', '$array2');")
}
What I am most confused about is how to make both arrays parse correctly into the DB. I hope I explained that correctly. Anything helps!
Here is an example of what it will need to look like:
Column 1 | Column 2 | Column 3
Dummy Data User Input1 User Input1
Dummy Data User Input2 User Input2
Dummy Data User Input3 User Input3
This is what I want it to look like with Column 2 being the first array and column 3 being the second array. Column 1 will always be the same.
revised based on your comments. should be easy to put into a sql stmt
This the way to pull values from the two arrays side by side for each index position
$array1 = #(1,2,3)
$array2 = #('a','b','c')
$counter = 0;
foreach ($file in $array1)
{
Write-Host $file $array2[$counter]
$counter +=1;
}
if you want an entire array stored in a column, you would need to convert possibly to string an delimit it
$array1 = #(1,2,3)
$array2 = #('a','b','c')
$counter = 0;
foreach ($file in $array1)
{
Write-Host $file ([string]::Join(',', $array2))
$counter +=1;
}
Based on the newly added expected result
$array1 = #(1, 2, 3)
$array2 = #("a", "b", "c")
$sqlQuery = [System.Text.StringBuilder]::new()
$sqlQuery.AppendLine("INSERT INTO tbl_File(Column1, Column2, Column3)")
$sqlQuery.AppendLine("VALUES ")
$hash = #{
A1 = $array1
A2 = $array2
}
$counter = $array1.count # Supposedly both arrays always contain same number of elements.
for ($i = 0; $i -le $counter - 1; $i++)
{
$sqlQuery.AppendLine("('Dummy Data', '" + $hash['A1'][$i] + "', '" + $hash['A2'][$i] + "')")
}
$sqlQuery.ToString();
Result is:
INSERT INTO tbl_File(Column1, Column2, Column3)
VALUES
('Dummy Data', '1', 'a'),
('Dummy Data', '2', 'b'),
('Dummy Data', '3', 'c')
(Old solution) Based on your comments I think this is the result you want in your table:
Column1 Column2 Column3
Dummy Data 1 2 3 a b c
This PS script generates the INSERT statement you need:
$array1 = #(1, 2, 3)
$array2 = #("a", "b", "c")
$sqlQuery = [System.Text.StringBuilder]::new()
$sqlQuery.AppendLine("INSERT INTO tbl_File(Column1, Column2, Column3)")
$sqlQuery.AppendLine("VALUES ")
$sqlQuery.AppendLine("('Dummy Data', '" + "$array1" + "', '" + "$array2" + "')")
$sqlQuery.ToString();
Result is:
INSERT INTO tbl_File(Column1, Column2, Column3)
VALUES
('Dummy Data', '1 2 3', 'a b c')
i have a perl script and i don't want to send a double request :
the request is '2018-03-15 12:30:00', 'Metric A', 62 and i want send only one time and not more :
in my mariadb bdd i have double line :
SELECT time, measurement, valueOne FROM `metric_values`;
results :
+---------------------+-----------------+----------+
| time | measurement | valueOne |
+---------------------+-----------------+----------+
| 2018-03-15 12:30:00 | Metric A | 62 |
| 2018-03-15 12:30:00 | Metric A | 62 |
my perl scipt :
use DBI;
open (FILE, 'logfile');
while (<FILE>) {
($word1, $word2, $word3, $word4, $word5, $word6, $word7, $word8, $word9, $word10, $word11, $word12, $word13, $word14) = split(" ");
$word13 =~ s/[^\d.]//g;
if ($word13 > 5) {
if ($word2 eq "Jan") {
$word2 = "01"
}
if ($word2 eq "Feb") {
$word2 = "02"
}
if ($word2 eq "Mar") {
$word2 = "03"
}
if ($word2 eq "Apr") {
$word2 = "04"
}
if ($word2 eq "May") {
$word2 = "05"
}
if ($word2 eq "Jun") {
$word2 = "06"
}
if ($word2 eq "Jul") {
$word2 = "07"
}
if ($word2 eq "Aug") {
$word2 = "08"
}
if ($word2 eq "Sep") {
$word2 = "09"
}
if ($word2 eq "Oct") {
$word2 = "10"
}
if ($word2 eq "Nov") {
$word2 = "11"
}
if ($word2 eq "Dec") {
$word2 = "12"
}
print "'$word5-$word2-$word3 $word4', $word11, $word13 \n";
}
# Connect to the database.
my $dbh = DBI->connect("DBI:mysql:database=db;host=ip",
"titi", 'mp!',
{'RaiseError' => 1}) ;
my $sth = $dbh->prepare(
"INSERT `metric_values` (time, measurement, valueOne) VALUES('$word5-$word2-$word3 $word4', $word11, $word13);")#result is ('2018-03-15 12:30:00', 'Metric A', 62)
or die "prepare statement failed: $dbh->errstr()";
$sth->execute() or die "execution failed: $dbh->errstr()";
print $sth->rows . " rows found.\n";
$sth->finish;
my log file:
Wed Oct 17 04:57:08 2018 : Resource = 'toto' cstep= 'titi' time =23.634s
Wed Oct 17 04:57:50 2018 : Resource = 'toto' cstep= 'titi' time =22.355s
thanks for your response
In a comment, you say this:
i execute this script every 5 minute and that create many same line in the table, i don't want same line in my table
I think this is what is happening.
Every five minutes you run your program. Each time you run the program you use exactly the same log file as input. So the same records get processed every time and new copies of the data are inserted on each run.
There's nothing wrong with your existing code. It's doing exactly what you've asked it to do. It's just not clever enough. You need to make it cleverer. You have a few options.
Remove from the log file the records that have been processed. That way you only insert each record once.
Add a flag to each record in your log file which indicates that it has been added to the database. You can then check that flag when processing the file and only insert records that don't have the flag.
Add an index to your table to ensure that it can only contain one copy of each record. You'll then need to change your code so it ignores any duplicate data errors that you get back from the database.
Use REPLACE instead of INSERT and ensure you have the correct primary key on your table to ensure that duplicate records aren't inserted.
Without knowing a log more about your particular application, it's hard to know which of these options is the best approach for you. I suspect you'll find the REPLACE option the easiest to implement.
Update: I hope you'll find some general comments on your code to be useful.
Your code to open the file works, of course, but it is some distance from current best practice. I recommend a) using a lexical filehandle, b) using the three-arg version of open() and c) checking the return value from the call.
open my $fh, '<', 'logfile'
or die "Could not open 'logfile': $!\n";
Using variables called $word1, $word2, etc is a terrible idea. A better idea would be to use an array:
my #words = split ' ',
If you really want individual variables, then please give them better names:
my ($day, $mon, $date, $time, $year, ... ) = split(' ');
Personally, I'd turn each record into a hash.
my #cols = qw[day mon date time year ... ];
# and then, in your loop
my %record;
#record{#cols} = split ' ';
Converting the month to a number the way you do it is clunky. Consider setting up a conversion hash.
my %months = (
Jan => 1,
Feb => 2,
...
);
Then your code becomes (assuming $mon instead of $word2):
$mon = sprintf '%02d', $months{$mon}
or die "$mon is not a valid month\n";
But, actually, you should use something like Time::Piece to deal with dates and times.
my $timestamp = "$day $mon $date $time $year";
my $tp = Time::Piece->strptime($timestamp, '%a %b %d %H:%M:%S $Y');
say $tp->ymd, ' ', $tp->hms;
I have about 20 columns in one row and not all columns are required to be filled in when row created also i dont want to cardcode name of every column in SQL query and on http.post request on frontend. All values are from form. My code:
var colNames, values []string
for k, v := range formData {
colNames = append(colNames, k)
values = append(values, v)
}
Now i have 2 arrays: one with column names and second with values to be inserted. I want to do something like this:
db.Query("insert into views (?,?,?,?,?,?) values (?,?,?,?,?,?)", colNames..., values...)
or like this:
db.Query("insert into views " + colNames + " values" + values)
Any suggestions?
Thanks!
I assume your code examples are just pseudo code but I'll state the obvious just in case.
db.Query("insert into views (?,?,?,?,?,?) values (?,?,?,?,?,?)", colNames..., values...)
This is invalid Go since you can only "unpack" the last argument to a function, and also invalid MySQL since you cannot use placeholders (?) for column names.
db.Query("insert into views " + colNames + " values" + values)
This is also invalid Go since you cannot concatenate strings with slices.
You could fromat the slices into strings that look like this:
colNamesString := "(col1, col2, col3)"
valuesString := "(val1, val2, val3)"
and now your second code example becomes valid Go and would compile but don't do this. If you do this your app becomes vulnerable to SQL injection and that's something you definitely don't want.
Instead do something like this:
// this can be a package level global and you'll need
// one for each table. Keep in mind that Go maps that
// are only read from are safe for concurrent use.
var validColNames = map[string]bool{
"col1": true,
"col2": true,
"col3": true,
// ...
}
// ...
var colNames, values []string
var phs string // placeholders for values
for k, v := range formData {
// check that column is valid
if !validColNames[k] {
return ErrBadColName
}
colNames = append(colNames, k)
values = append(values, v)
phs += "?,"
}
if len(phs) > 0 {
phs = phs[:len(phs)-1] // drop the last comma
}
phs = "(" + phs + ")"
colNamesString := "(" + strings.Join(colNames, ",") + ")"
query := "insert into views " + colNamesString + phs
db.Query(query, values...)
I was wondering if it is possible to combine column values based upon a condition. Let me explain...
Let say my data looks like this
Id name offset
1 Jan 100
2 Janssen 104
3 Klaas 150
4 Jan 160
5 Janssen 164
An my output should be this
Id fullname offsets
1 Jan Janssen [ 100, 160 ]
I would like to combine the name values from two rows where the offset of the two rows are no more apart then 1 character.
My question is if this type of data manipulation is possible with and if it is could someone share some code and explaination?
Please be gentle but this little piece of code return some what what I want...
ArrayList<String> persons = new ArrayList<String>();
// write your code here
String _previous = "";
//Sample output form entities.txt
//USER.A-GovDocs-f83c6ca3-9585-4c66-b9b0-f4c3bd57ccf4,Berkowitz,PERSON,9,10660
//USER.A-GovDocs-f83c6ca3-9585-4c66-b9b0-f4c3bd57ccf4,Marottoli,PERSON,9,10685
File file = new File("entities.txt");
try {
//
// Create a new Scanner object which will read the data
// from the file passed in. To check if there are more
// line to read from it we check by calling the
// scanner.hasNextLine() method. We then read line one
// by one till all line is read.
//
Scanner scanner = new Scanner(file);
while (scanner.hasNextLine()) {
if(_previous == "" || _previous == null)
_previous = scanner.nextLine();
String _current = scanner.nextLine();
//Compare the lines, if there offset is = 1
int x = Integer.parseInt(_previous.split(",")[3]) + Integer.parseInt(_previous.split(",")[4]);
int y = Integer.parseInt(_current.split(",")[4]);
if(y-x == 1){
persons.add(_previous.split(",")[1] + " " + _current.split(",")[1]);
if(scanner.hasNextLine()){
_current = scanner.nextLine();
}
}else{
persons.add(_previous.split(",")[1]);
}
_previous = _current;
}
} catch (Exception e) {
e.printStackTrace();
}
for(String person : persons){
System.out.println(person);
}
Working of this piece sample data
USER.A-GovDocs-f83c6ca3-9585-4c66-b9b0-f4c3bd57ccf4,Richard,PERSON,7,2732
USER.A-GovDocs-f83c6ca3-9585-4c66-b9b0-f4c3bd57ccf4,Marottoli,PERSON,9,2740
USER.A-GovDocs-f83c6ca3-9585-4c66-b9b0-f4c3bd57ccf4,Marottoli,PERSON,9,2756
USER.A-GovDocs-f83c6ca3-9585-4c66-b9b0-f4c3bd57ccf4,Marottoli,PERSON,9,3093
USER.A-GovDocs-f83c6ca3-9585-4c66-b9b0-f4c3bd57ccf4,Marottoli,PERSON,9,3195
USER.A-GovDocs-f83c6ca3-9585-4c66-b9b0-f4c3bd57ccf4,Berkowitz,PERSON,9,3220
USER.A-GovDocs-f83c6ca3-9585-4c66-b9b0-f4c3bd57ccf4,Berkowitz,PERSON,9,10660
USER.A-GovDocs-f83c6ca3-9585-4c66-b9b0-f4c3bd57ccf4,Marottoli,PERSON,9,10685
USER.A-GovDocs-f83c6ca3-9585-4c66-b9b0-f4c3bd57ccf4,Lea,PERSON,3,10858
USER.A-GovDocs-f83c6ca3-9585-4c66-b9b0-f4c3bd57ccf4,Lea,PERSON,3,11063
USER.A-GovDocs-f83c6ca3-9585-4c66-b9b0-f4c3bd57ccf4,Ken,PERSON,3,11186
USER.A-GovDocs-f83c6ca3-9585-4c66-b9b0-f4c3bd57ccf4,Marottoli,PERSON,9,11234
USER.A-GovDocs-f83c6ca3-9585-4c66-b9b0-f4c3bd57ccf4,Berkowitz,PERSON,9,17073
USER.A-GovDocs-f83c6ca3-9585-4c66-b9b0-f4c3bd57ccf4,Lea,PERSON,3,17095
USER.A-GovDocs-f83c6ca3-9585-4c66-b9b0-f4c3bd57ccf4,Stephanie,PERSON,9,17330
USER.A-GovDocs-f83c6ca3-9585-4c66-b9b0-f4c3bd57ccf4,Putt,PERSON,4,17340
Which produces this output
Richard Marottoli
Marottoli
Marottoli
Marottoli
Berkowitz
Berkowitz
Marottoli
Lea
Lea
Ken
Marottoli
Berkowitz
Lea
Stephanie Putt
Kind regards
Load the table using below create table
drop table if exists default.stack;
create external table default.stack
(junk string,
name string,
cat string,
len int,
off int
)
ROW FORMAT DELIMITED
FIELDS terminated by ','
STORED AS INPUTFORMAT
'org.apache.hadoop.mapred.TextInputFormat'
OUTPUTFORMAT
'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat'
location 'hdfs://nameservice1/....';
Use below query to get your desired output.
select max(name), off from (
select CASE when b.name is not null then
concat(b.name," ",a.name)
else
a.name
end as name
,Case WHEN b.off1 is not null
then b.off1
else a.off
end as off
from default.stack a
left outer join (select name
,len+off+ 1 as off
,off as off1
from default.stack) b
on a.off = b.off ) a
group by off
order by off;
I have tested this it generates your desired result.
I want to migrate my iPhone app to a new database version. Since I don't have some version saved, I need to check if certain column names exist.
This Stackoverflow entry suggests doing the select
SELECT sql FROM sqlite_master
WHERE tbl_name = 'table_name' AND type = 'table'
and parse the result.
Is that the common way? Alternatives?
PRAGMA table_info(table_name);
will get you a list of all the column names.
If you do
.headers ON
you will get the desired result.
If you have the sqlite database, use the sqlite3 command line program and these commands:
To list all the tables in the database:
.tables
To show the schema for a given tablename:
.schema tablename
Just for super noobs like me wondering how or what people meant by
PRAGMA table_info('table_name')
You want to use use that as your prepare statement as shown below. Doing so selects a table that looks like this except is populated with values pertaining to your table.
cid name type notnull dflt_value pk
---------- ---------- ---------- ---------- ---------- ----------
0 id integer 99 1
1 name 0 0
Where id and name are the actual names of your columns. So to get that value you need to select column name by using:
//returns the name
sqlite3_column_text(stmt, 1);
//returns the type
sqlite3_column_text(stmt, 2);
Which will return the current row's column's name. To grab them all or find the one you want you need to iterate through all the rows. Simplest way to do so would be in the manner below.
//where rc is an int variable if wondering :/
rc = sqlite3_prepare_v2(dbPointer, "pragma table_info ('your table name goes here')", -1, &stmt, NULL);
if (rc==SQLITE_OK)
{
//will continue to go down the rows (columns in your table) till there are no more
while(sqlite3_step(stmt) == SQLITE_ROW)
{
sprintf(colName, "%s", sqlite3_column_text(stmt, 1));
//do something with colName because it contains the column's name
}
}
If you want the output of your queries to include columns names and be correctly aligned as columns, use these commands in sqlite3:
.headers on
.mode column
You will get output like:
sqlite> .headers on
sqlite> .mode column
sqlite> select * from mytable;
id foo bar
---------- ---------- ----------
1 val1 val2
2 val3 val4
An alternative way to get a list of column names not mentioned here that is cross platform and does not rely on the sqlite3.exe shell is to select from the PRAGMA_TABLE_INFO() table value function.
SELECT name FROM PRAGMA_TABLE_INFO('your_table');
name
tbl_name
rootpage
sql
You can check if a certain column exists by querying:
SELECT 1 FROM PRAGMA_TABLE_INFO('your_table') WHERE name='column1';
1
This is what you use if you don't want to parse the result of select sql from sqlite_master or pragma table_info.
Note this feature is experimental and was added in SQLite version 3.16.0 (2017-01-02).
Reference:
https://www.sqlite.org/pragma.html#pragfunc
To get a list of columns you can simply use:
.schema tablename
I know it is an old thread, but recently I needed the same and found a neat way:
SELECT c.name FROM pragma_table_info('your_table_name') c;
When you run the sqlite3 cli, typing in:
sqlite3 -header
will also give the desired result
.schema table_name
This will list down the column names of the table from the database.
Hope this will help!!!
you can use Like statement if you are searching for any particular column
ex:
SELECT * FROM sqlite_master where sql like('%LAST%')
This command below sets column names:
.header on
Then, this is how it looks like below:
sqlite> select * from user;
id|first_name|last_name|age
1|Steve|Jobs|56
2|Bill|Gates|66
3|Mark|Zuckerberg|38
And this command below unsets column names:
.header off
Then, this is how it looks like below:
sqlite> select * from user;
1|Steve|Jobs|56
2|Bill|Gates|66
3|Mark|Zuckerberg|38
And these commands show the details of the command ".header":
.help .header
Or:
.help header
Then, this is how it looks like below:
sqlite> .help .header
.headers on|off Turn display of headers on or off
In addition, this command below sets the output mode "box":
.mode box
Then, this is how it looks like below:
sqlite> select * from user;
┌────┬────────────┬────────────┬─────┐
│ id │ first_name │ last_name │ age │
├────┼────────────┼────────────┼─────┤
│ 1 │ Steve │ Jobs │ 56 │
│ 2 │ Bill │ Gates │ 66 │
│ 3 │ Mark │ Zuckerberg │ 38 │
└────┴────────────┴────────────┴─────┘
And, this command below sets the output mode "table":
.mode table
Then, this is how it looks like below:
sqlite> select * from user;
+----+------------+------------+-----+
| id | first_name | last_name | age |
+----+------------+------------+-----+
| 1 | Steve | Jobs | 56 |
| 2 | Bill | Gates | 66 |
| 3 | Mark | Zuckerberg | 38 |
+----+------------+------------+-----+
And these commands show the details of the command ".mode":
.help .mode
Or:
.help mode
Then, this is how it looks like below:
sqlite> .help .mode
.import FILE TABLE Import data from FILE into TABLE
Options:
--ascii Use \037 and \036 as column and row separators
--csv Use , and \n as column and row separators
--skip N Skip the first N rows of input
--schema S Target table to be S.TABLE
-v "Verbose" - increase auxiliary output
Notes:
* If TABLE does not exist, it is created. The first row of input
determines the column names.
* If neither --csv or --ascii are used, the input mode is derived
from the ".mode" output mode
* If FILE begins with "|" then it is a command that generates the
input text.
.mode MODE ?OPTIONS? Set output mode
MODE is one of:
ascii Columns/rows delimited by 0x1F and 0x1E
box Tables using unicode box-drawing characters
csv Comma-separated values
column Output in columns. (See .width)
html HTML <table> code
insert SQL insert statements for TABLE
json Results in a JSON array
line One value per line
list Values delimited by "|"
markdown Markdown table format
qbox Shorthand for "box --width 60 --quote"
quote Escape answers as for SQL
table ASCII-art table
tabs Tab-separated values
tcl TCL list elements
OPTIONS: (for columnar modes or insert mode):
--wrap N Wrap output lines to no longer than N characters
--wordwrap B Wrap or not at word boundaries per B (on/off)
--ww Shorthand for "--wordwrap 1"
--quote Quote output text as SQL literals
--noquote Do not quote output text
TABLE The name of SQL table used for "insert" mode
In order to get the column information you can use the following snippet:
String sql = "select * from "+oTablename+" LIMIT 0";
Statement statement = connection.createStatement();
ResultSet rs = statement.executeQuery(sql);
ResultSetMetaData mrs = rs.getMetaData();
for(int i = 1; i <= mrs.getColumnCount(); i++)
{
Object row[] = new Object[3];
row[0] = mrs.getColumnLabel(i);
row[1] = mrs.getColumnTypeName(i);
row[2] = mrs.getPrecision(i);
}
//JUST little bit modified the answer of giuseppe which returns array of table columns
+(NSMutableArray*)tableInfo:(NSString *)table{
sqlite3_stmt *sqlStatement;
NSMutableArray *result = [NSMutableArray array];
const char *sql = [[NSString stringWithFormat:#"PRAGMA table_info('%#')",table] UTF8String];
if(sqlite3_prepare(md.database, sql, -1, &sqlStatement, NULL) != SQLITE_OK)
{
NSLog(#"Problem with prepare statement tableInfo %#",
[NSString stringWithUTF8String:(const char *)sqlite3_errmsg(md.database)]);
}
while (sqlite3_step(sqlStatement)==SQLITE_ROW)
{
[result addObject:
[NSString stringWithUTF8String:(char*)sqlite3_column_text(sqlStatement, 1)]];
}
return result;
}
.schema
in sqlite console when you have you're inside the table
it looks something like this for me ...
sqlite>.schema
CREATE TABLE players(
id integer primary key,
Name varchar(255),
Number INT,
Team varchar(255)
This is an old question, but here is an alternative answer that retrieves all the columns in the SQLite database, with the name of the associated table for each column :
WITH tables AS (SELECT name tableName, sql
FROM sqlite_master WHERE type = 'table' AND tableName NOT LIKE 'sqlite_%')
SELECT fields.name, fields.type, tableName
FROM tables CROSS JOIN pragma_table_info(tables.tableName) fields
This returns this type of result:
{
"name": "id",
"type": "integer",
"tableName": "examples"
}, {
"name": "content",
"type": "text",
"tableName": "examples"
}
For a simple table containing an identifier and a string content.
function getDetails(){
var data = [];
dBase.executeSql("PRAGMA table_info('table_name') ", [], function(rsp){
if(rsp.rows.length > 0){
for(var i=0; i<rsp.rows.length; i++){
var o = {
name: rsp.rows.item(i).name,
type: rsp.rows.item(i).type
}
data.push(o);
}
}
alert(rsp.rows.item(0).name);
},function(error){
alert(JSON.stringify(error));
});
}
-(NSMutableDictionary*)tableInfo:(NSString *)table
{
sqlite3_stmt *sqlStatement;
NSMutableDictionary *result = [[NSMutableDictionary alloc] init];
const char *sql = [[NSString stringWithFormat:#"pragma table_info('%s')",[table UTF8String]] UTF8String];
if(sqlite3_prepare(db, sql, -1, &sqlStatement, NULL) != SQLITE_OK)
{
NSLog(#"Problem with prepare statement tableInfo %#",[NSString stringWithUTF8String:(const char *)sqlite3_errmsg(db)]);
}
while (sqlite3_step(sqlStatement)==SQLITE_ROW)
{
[result setObject:#"" forKey:[NSString stringWithUTF8String:(char*)sqlite3_column_text(sqlStatement, 1)]];
}
return result;
}
I know it's too late but this will help other.
To find the column name of the table, you should execute select * from tbl_name and you will get the result in sqlite3_stmt *. and check the column iterate over the total fetched column. Please refer following code for the same.
// sqlite3_stmt *statement ;
int totalColumn = sqlite3_column_count(statement);
for (int iterator = 0; iterator<totalColumn; iterator++) {
NSLog(#"%s", sqlite3_column_name(statement, iterator));
}
This will print all the column names of the result set.
I was able to retrieve table names with corresponding columns by using one sql query, but columns output is comma separated. I hope it helps somebody
SELECT tbl_name, (SELECT GROUP_CONCAT(name, ',') FROM PRAGMA_TABLE_INFO(tbl_name)) as columns FROM sqlite_schema WHERE type = 'table';
Get a list of tables and columns as a view:
CREATE VIEW Table_Columns AS
SELECT m.tbl_name AS TableView_Name, m.type AS TableView, cid+1 AS Column, p.*
FROM sqlite_master m, Pragma_Table_Info(m.tbl_name) p
WHERE m.type IN ('table', 'view') AND
( m.tbl_name = 'mypeople' OR m.tbl_name LIKE 'US_%') -- filter tables
ORDER BY m.tbl_name;
//Called when application is started. It works on Droidscript, it is tested
function OnStart()
{
//Create a layout with objects vertically centered.
lay = app.CreateLayout( "linear", "VCenter,FillXY" );
//Create a text label and add it to layout.
txt = app.CreateText( "", 0.9, 0.4, "multiline" )
lay.AddChild( txt );
app.AddLayout(lay);
db = app.OpenDatabase( "MyData" )
//Create a table (if it does not exist already).
db.ExecuteSql( "drop table if exists test_table" )
db.ExecuteSql( "CREATE TABLE IF NOT EXISTS test_table " +
"(id integer primary key, data text, num integer)",[],null, OnError )
db.ExecuteSql( "insert into test_table values (1,'data10',100),
(2,'data20',200),(3,'data30',300)")
//Get all the table rows.
DisplayAllRows("SELECT * FROM test_table");
DisplayAllRows("select *, id+100 as idplus, 'hahaha' as blabla from
test_table order by id desc;")
}
//function to display all records
function DisplayAllRows(sqlstring) // <-- can you use for any table not need to
// know column names, just use a *
// example:
{
//Use all rows what is in ExecuteSql (try any, it will works fine)
db.ExecuteSql( sqlstring, [], OnResult, OnError )
}
//Callback to show query results in debug.
function OnResult( res )
{
var len = res.rows.length;
var s = txt.GetText();
// ***********************************************************************
// This is the answer how to read column names from table:
for(var ColumnNames in res.rows.item(0)) s += " [ "+ ColumnNames +" ] "; // "[" & "]" optional, i use only in this demo
// ***********************************************************************
//app.Alert("Here is all Column names what Select from your table:\n"+s);
s+="\n";
for(var i = 0; i < len; i++ )
{
var rows = res.rows.item(i)
for (var item in rows)
{
s += " " + rows[item] + " ";
}
s+="\n\n";
}
//app.Alert(s);
txt.SetText( s )
}
//Callback to show errors.
function OnError( msg )
{
app.Alert( "Error: " + msg )
}
If you're using the SQLite3, INFORMATION_SCHEMA is not supported. Use PRAGMA table_info instead. This will return 6 rows of information about the table. To fetch the column name (row2), use a for loop like the following
cur.execute("PRAGMA table_info(table_name)") # fetches the 6 rows of data
records = cur.fetchall()
print(records)
for row in records:
print("Columns: ", row[1])
For use in Python with sqlite3
Top answer PRAGMA table_info() returns a list of tuples, which might not be suitable for further processing, e.g.:
[(0, 'id', 'INTEGER', 0, None, 0),
(1, 'name', 'TEXT', 0, None, 0),
(2, 'age', 'INTEGER', 0, None, 0),
(3, 'profession', 'TEXT', 0, None, 0)]
When using sqlite3 in Python, simply add a list comprehension in the end to filter out unwanted information.
import sqlite3 as sq
def col_names(t_name):
with sq.connect('file:{}.sqlite?mode=ro'.format(t_name),uri=True) as conn:
cursor = conn.cursor()
cursor.execute("PRAGMA table_info({}) ".format(t_name))
data = cursor.fetchall()
return [i[1] for i in data]
col_names("your_table_name")
Result
["id","name","age","profession"]
DISCLAIMER: Do not use in production as this snippet is subject to possible SQL injection!