Useful openssl commands to generate certificates and keys

I hope the following will come handy when it comes to generating key pairs and certificates.

# Generate a Private Key
openssl genrsa -out privatekey.pem 2048

# Generate a self-signed certificate
openssl req -new -x509 -key privatekey.pem -out self_signed_certificate.pem -days 365

# Convert PEM certificate to CER format
openssl x509 -inform PEM -in self_signed_certificate.pem -outform DER -out self_signed_certificate.cer

# Convert a PEM certificate to a PFX (PKCS#12) file
openssl pkcs12 -export -out certificate.pfx -inkey privatekey.pem -in self_signed_certificate.pem

# Extract a private key from a PFX file (contain bag attributes)
# openssl pkcs12 -in certificate.pfx -nocerts -nodes -out privatekey_frompfx.pem
openssl pkcs12 -in certificate.pfx -nocerts -nodes -out privatekey_frompfx.key

# Extract a private key (no bag attributes) - identical to privatekey.pem
openssl rsa -in privatekey_frompfx.key -out privatekey_frompfx.key

# Extract public key from key pair
openssl rsa -in privatekey_frompfx.key -pubout -out publickey.key
#openssl rsa -in privatekey.pem -pubout -out publickey2.key

# Convert CER to CRT
openssl x509 -inform DER -in self_signed_certificate.cer -out self_signed_certificate.crt
#openssl x509 -inform PEM -in self_signed_certificate.cer -out self_signed_certificate.crt

# Convert CRT to CER
openssl x509 -in self_signed_certificate.crt -outform DER -out self_signed_certificate2.cer

#####
# Generate a Certificate Signing Request (CSR) - optional if going to generate a self-signed
#openssl req -new -key privatekey.pem -out certificate_request.csr
#openssl x509 -req -in certificate_request.csr -signkey privatekey.pem -out self_signed_certificate3.crt

Oracle: Find out total number of records of all tables

An efficient method to find out the total record counts of all tables in an Oracle database.

select table_name,
  to_number(extractvalue(xmltype(dbms_xmlgen.getxml('select count(*) c from '||owner||'.'||table_name)),'/ROWSET/ROW/C')) as count
from all_tables
where owner = 'SchemaName';

Hope it helps.

MSSQL: Find out total number of records of all tables

An efficient method to find out the total record counts of all tables in a MSSQL database.

SELECT tbl.name, CAST(p.rows AS int) 'count', tbl.schema_id, SCHEMA_NAME(tbl.schema_id) schema_name
FROM
  sys.tables AS tbl
  INNER JOIN sys.indexes AS idx ON idx.object_id = tbl.object_id AND idx.index_id < 2
  INNER JOIN sys.partitions AS p ON p.object_id = CAST(tbl.object_id AS int) AND p.index_id = idx.index_id
--WHERE ((SCHEMA_NAME(tbl.schema_id) = 'dbo'))
ORDER BY 2 DESC

Hope it helps.

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LTA's Official MRT Map 2023

The below is LTA's official MRT map that includes both current and future train network.

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The below is LTA's official MRT map that includes both current and future train network.

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