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SQL Standards

SQL Standards

Queries

General standards

We always use backticks ` around the table- and column names. `creature_loot_template`.

We always use single quotes around string values ' ' but NEVER around an integer.

We never include the database name in queries.

INSERT & DELETE

We always DELETE before an INSERT to ensure we always put fields in the query and that no errors occur.

Your DELETE statement should always include at least one column with the PRIMARY key.

Wrong:

INSERT INTO `creature_loot_template` (3, 884, 0, 40, 1, 1, 0, 1, 1, 'Comment');

REPLACE INTO `creature_loot_template` (3, 884, 0, 40, 1, 1, 0, 1, 1, 'Comment');

Correct:

DELETE FROM `creature_loot_template` WHERE `entry` = 3 AND `item` = 884;
INSERT INTO `creature_loot_template` (`Entry`, `Item`, `Reference`, `Chance`, `QuestRequired`, `LootMode`, `GroupId`, `MinCount`, `MaxCount`, `Comment`) VALUES 
(3, 884, 0, 40, 1, 1, 0, 1, 1, 'Comment');

When performing DELETE queries, always specify more than one field. In particular, specify at least one primary key present in the table and another accompanying field.

Wrong:

DELETE FROM `creature_loot_template` WHERE `item` = 884;

Correct:

DELETE FROM `creature_loot_template` WHERE `entry` = 3 AND `item` = 884;

UPDATE

Make sure your queries are precise so you avoid changing something you do not want to edit.

Rule of thumb, always include all primary keys in your WHERE clause.

Wrong:

UPDATE `creature_loot_template` SET `Chance` = 100 WHERE `item` = 884;

Correct:

UPDATE `creature_loot_template` SET `Chance` = 100 WHERE `entry` = 3 AND `item` = 884;

Variables

Variables can be good when you change the same entry in several places to avoid mistakes.

Before:

UPDATE `creature_template` SET `AIName` = 'SmartAI' WHERE `entry` = 7727;

DELETE FROM `smart_scripts` WHERE `entryorguid` = 7727 AND `source_type` = 0;
INSERT INTO `smart_scripts` (`entryorguid`, `source_type`, `id`, `link`, `event_type`, `event_phase_mask`, `event_chance`, `event_flags`, `event_param1`, `event_param2`, `event_param3`, `event_param4`, `event_param5`, `action_type`, `action_param1`, `action_param2`, `action_param3`, `action_param4`, `action_param5`, `action_param6`, `target_type`, `target_param1`, `target_param2`, `target_param3`, `target_param4`, `target_x`, `target_y`, `target_z`, `target_o`, `comment`) VALUES 
(7727, 0, 0, 0, 0, 0, 100, 0, 2000, 4000, 2000, 4000, 0, 11, 930, 64, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 'Grimtotem Shaman - In Combat - Cast \'Chain Lightning\''),
(7727, 0, 1, 0, 2, 0, 100, 1, 0, 50, 0, 0, 0, 11, 8499, 2, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 'Grimtotem Shaman - Between 0-50% Health - Cast \'Fire Nova\' (No Repeat)'),
(7727, 0, 2, 0, 2, 0, 100, 0, 0, 30, 0, 0, 0, 11, 8005, 64, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 'Grimtotem Shaman - Between 0-30% Health - Cast \'Healing Wave\'');

After:

-- Grimtotem Shaman SAI
SET @ENTRY := 7727;
SET @SPELL1 := 930;
SET @SPELL2 := 8499;
SET @SPELL3 := 8005;

UPDATE `creature_template` SET `AIName` = 'SmartAI' WHERE `entry` = @ENTRY;

DELETE FROM `smart_scripts` WHERE `entryorguid` = @ENTRY AND `source_type` = 0;
INSERT INTO `smart_scripts` (`entryorguid`, `source_type`, `id`, `link`, `event_type`, `event_phase_mask`, `event_chance`, `event_flags`, `event_param1`, `event_param2`, `event_param3`, `event_param4`, `event_param5`, `action_type`, `action_param1`, `action_param2`, `action_param3`, `action_param4`, `action_param5`, `action_param6`, `target_type`, `target_param1`, `target_param2`, `target_param3`, `target_param4`, `target_x`, `target_y`, `target_z`, `target_o`, `comment`) VALUES 
(@ENTRY, 0, 0, 0, 0, 0, 100, 0, 2000, 4000, 2000, 4000, 0, 11, @SPELL1, 64, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 'Grimtotem Shaman - In Combat - Cast \'Chain Lightning\''),
(@ENTRY, 0, 1, 0, 2, 0, 100, 1, 0, 50, 0, 0, 0, 11, @SPELL2, 2, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 'Grimtotem Shaman - Between 0-50% Health - Cast \'Fire Nova\' (No Repeat)'),
(@ENTRY, 0, 2, 0, 2, 0, 100, 0, 0, 30, 0, 0, 0, 11, @SPELL3, 64, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 'Grimtotem Shaman - Between 0-30% Health - Cast \'Healing Wave\'');

Compact queries

We always keep the code as compact as possible to limit the size of the files and decrease the number of queries needed to run.

Wrong:

DELETE FROM `table_1` WHERE `entry` = 1000;
DELETE FROM `table_1` WHERE `entry` = 2000;
DELETE FROM `table_1` WHERE `entry` = 3000;


INSERT INTO `table_1` VALUES (1000, ...);
INSERT INTO `table_1` VALUES (2000, ...);
INSERT INTO `table_1` VALUES (3000, ...);

UPDATE `table_1` SET `field_1` = 'someValue' WHERE `entry` = 1000;
UPDATE `table_1` SET `field_1` = 'someValue' WHERE `entry` = 2000;
UPDATE `table_1` SET `field_1` = 'someValue' WHERE `entry` = 3000;

Correct:

DELETE FROM `table_1` WHERE `entry` IN (1000, 2000, 3000);

INSERT INTO `table_1` VALUES
(1000, ...),
(2000, ...),
(3000, ...);

UPDATE `table_1` SET `field_1` = 'someValue' WHERE `entry` IN (1000, 2000, 3000);

Flags & Bits

For fields in the database where we work with flags, it is always preferred that we add or remove flags instead of overriding them.

Wrong:

UPDATE `creature_template` SET `mechanic_immune_mask` = 617299803 WHERE `entry` = 7727;

Correct:

-- Adding flags
UPDATE `creature_template` SET `mechanic_immune_mask`=`mechanic_immune_mask`|64|256|1024 WHERE `entry` = 7727;

-- Removing flags
UPDATE `creature_template` SET `mechanic_immune_mask`=`mechanic_immune_mask`&~(64|256|1024) WHERE `entry` = 7727;

Tables and Columns

Naming of tables and columns

For the most part, tables should be written in snake case, and columns should be written in upper camel case.

Tables:

broadcast_text
creature_loot_template
points_of_interest

Columns:

MaleText
QuestRequired
PositionX

In the case of column names with acronyms (e.g. GUID, ID, NPC, etc) the letters in the acronym should be uppercase.

Wrong:

Itemguid
DisplayId
RequiredNpcOrGoCount

Correct:

ItemGUID
DisplayID
RequiredNPCOrGOCount

Integers

We do not define the width of an integer when we create new columns. (Width is deprecated in later versions of MySQL 8)

TINYINT(M)   -> TINYINT
SMALLINT(M)  -> SMALLINT
INT(M)       -> INT
BIGINT(M)    -> BIGINT

BOOL         -> Never used, a synonym for TINYINT. 0 = false <>0 = true

We never use MEDIUMINT. Use INT instead!

Float, Double, Decimal

These data types cannot be UNSIGNED and therefore we use CHECK CONSTRAINTS instead. (UNSIGNED Float, Double, Decimal is deprecated in later versions of MySQL 8)

FLOAT UNSIGNED -> CHECK (`column`>=0)

Check Constraints

You can see here how check constraints are made.

All active Check Constraints can be found by using this query:

-- MySQL 8.0 and newer
SELECT * FROM information_schema.CHECK_CONSTRAINTS;

-- MySQL 5.7
SELECT * FROM information_schema.TABLE_CONSTRAINTS;

Charset

We always use utf8mb4 as the charset

Collation

We always use utf8mb4_unicode_ci as the collation

The only exception is where we use a character name, here we need to use utf8mb4_bin to allow the name to be accent-sensitive.

Engine

We always use InnoDB as the engine

Row Format

We always use DEFAULT as the row format

Dummy script for table

DROP TABLE IF EXISTS `our_table_name`;
CREATE TABLE `our_table_name` (
  `aColumnName` INT UNSIGNED NOT NULL DEFAULT '69' COMMENT 'ColumnComment',
  `aSecondName` VARCHAR(100) NOT NULL DEFAULT '',
  PRIMARY KEY (`aColumnName`),
  CONSTRAINT `our_table_name_chk_1` CHECK (`aColumnName` >= 0)
)
COMMENT = 'TableComment'
CHARSET = utf8mb4
COLLATE = utf8mb4_unicode_ci
ENGINE = InnoDB
ROW_FORMAT = DEFAULT
;

Note for SQL reviewer

When we work with GUIDs, make sure that we use as low entries as possible to fill out the gaps in the database. This can easily be done with tools like Unused GUID Searcher.