Mysql/CheatSheet: Difference between revisions
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* constraints | * constraints | ||
<pre> | |||
NOT NULL | |||
UNIQUE | |||
PRIMARY KEY (NOT NULL and UNIQUE) | |||
FOREIGN KEY | |||
CHECK | |||
* | DEFAULT | ||
INDEX | |||
</pre> | |||
* data types | |||
<pre> | |||
TINYINT (A very small integer: -128/128 or 0/255) | |||
SMALLINT (A small integer: -32768/32767 or 0/65535) | |||
MEDIUMINT (A medium-sized integer: -8388608/8388607 or 0/16777215) | |||
INT (A standard integer: -2147483648/2147483647 or 0/4294967295) | |||
BIGINT (A large integer: -9223372036854775808/9223372036854775807 or 0/18446744073709551615) | |||
DECIMAL(P,D) (A fixed-point number: P=digits, D=decimals) | |||
FLOAT (A single-precision floating point number | |||
DOUBLE (A double-precision floating point number | |||
BIT (A bit field | |||
CHAR (A fixed-length nonbinary (character) string | |||
VARCHAR (A variable-length non-binary string | |||
BINARY (A fixed-length binary string | |||
VARBINARY (A variable-length binary string | |||
TINYBLOB (A very small BLOB (binary large object) | |||
BLOB (A small BLOB | |||
MEDIUMBLOB (A medium-sized BLOB | |||
LONGBLOB (A large BLOB | |||
TINYTEXT (A very small non-binary string | |||
TEXT (A small non-binary string | |||
MEDIUMTEXT (A medium-sized non-binary string | |||
LONGTEXT (A large non-binary string | |||
ENUM (An enumeration; each column value may be assigned one enumeration member | |||
SET (A set; each column value may be assigned zero or more SET members | |||
</pre> | |||
== other == | == other == |
Revision as of 08:11, 16 June 2020
Databases
- Create
CREATE DATABASE [IF NOT EXISTS] database_name;
- Use
USE database_name;
- Delete
DROP DATABASE [IF EXISTS] database_name;
- List all
SHOW DATABASES;
- Storage Engines
- MyISAM (optimized for compression and speed. portable. not transaction safe. used to be default)
- InnoDB (optimized for speed. portable. portable. default)
- MERGE
- MEMORY (HEAP)
- ARCHIVE
- CSV
- FEDERATED
Tables
- list
SHOW TABLES;
- create
CREATE TABLE [IF NOT EXISTS] table_name( column1 datatype constraint, column2 datatype constraint );
CREATE TABLE IF NOT EXISTS cars( vehicle_id INT AUTO_INCREMENT PRIMARY KEY, title VARCHAR(255) NOT NULL, first_seen DATE, description TEXT );
- constraints
NOT NULL UNIQUE PRIMARY KEY (NOT NULL and UNIQUE) FOREIGN KEY CHECK DEFAULT INDEX
- data types
TINYINT (A very small integer: -128/128 or 0/255) SMALLINT (A small integer: -32768/32767 or 0/65535) MEDIUMINT (A medium-sized integer: -8388608/8388607 or 0/16777215) INT (A standard integer: -2147483648/2147483647 or 0/4294967295) BIGINT (A large integer: -9223372036854775808/9223372036854775807 or 0/18446744073709551615) DECIMAL(P,D) (A fixed-point number: P=digits, D=decimals) FLOAT (A single-precision floating point number DOUBLE (A double-precision floating point number BIT (A bit field CHAR (A fixed-length nonbinary (character) string VARCHAR (A variable-length non-binary string BINARY (A fixed-length binary string VARBINARY (A variable-length binary string TINYBLOB (A very small BLOB (binary large object) BLOB (A small BLOB MEDIUMBLOB (A medium-sized BLOB LONGBLOB (A large BLOB TINYTEXT (A very small non-binary string TEXT (A small non-binary string MEDIUMTEXT (A medium-sized non-binary string LONGTEXT (A large non-binary string ENUM (An enumeration; each column value may be assigned one enumeration member SET (A set; each column value may be assigned zero or more SET members