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https://dev.mysql.com/doc/refman/5.7/en/password-hashing.html
A 4.1 or later server generates long hashes only if certain conditions are met: The Password column must be wide enough to hold long values and old_passwords must not be set to 1. If the column has not been updated and still has the pre-4.1 width of ...The client can do this by using the PASSWORD() function to generate a password hash, or by using a password-generating statement (CREATE USER, GRANT, or SET ... Note The ...
https://dev.mysql.com/doc/refman/5.7/en/column-count-limit.html
This section describes limits on the number of columns in tables and the size of individual rows. Column Count Limits Row Size Limits Column Count Limits MySQL has hard limit of 4096 columns per table, but the effective maximum may be less for a ...
https://dev.mysql.com/doc/refman/5.7/en/innodb-auto-increment-handling.html
Once a value is generated for an auto-increment column, it cannot be rolled back, whether or not the “INSERT-like” statement is completed, and whether or not the containing transaction is rolled back. Specifying NULL or 0 for the AUTO_INCREMENT ... InnoDB provides a configurable locking mechanism that can significantly improve scalability and performance of SQL statements that add rows to tables with AUTO_INCREMENT ...
https://dev.mysql.com/doc/refman/5.7/en/partitioning-columns-list.html
This is a variant of LIST partitioning that enables the use of multiple columns as partition keys, and for columns of data types other than integer types to be used as partitioning columns; you can use string types, DATE, and DATETIME columns. In ...
https://dev.mysql.com/doc/refman/5.7/en/multiple-column-indexes.html
MySQL can create composite indexes (that is, indexes on multiple columns). For certain data types, you can index a prefix of the column (see Section 8.3.4, “Column Indexes”). MySQL can use multiple-column indexes for queries that test all the ...The index can be used for lookups in queries that specify values in a known range for combinations of last_name and first_name ...
https://dev.mysql.com/doc/refman/5.7/en/charset-column.html
Every “character” column (that is, a column of type CHAR, VARCHAR, a TEXT type, or any synonym) has a column character set and a column collation. CREATE TABLE t1 ( col1 CHAR(10) CHARACTER SET utf8 COLLATE utf8_unicode_ci ) CHARACTER SET latin1 ...If CHARACTER SET charset_name is specified without COLLATE, character set charset_name and its default collation are ...
https://dev.mysql.com/doc/refman/5.7/en/partitioning-columns.html
The next two sections discuss COLUMNS partitioning, which are variants on RANGE and LIST partitioning. COLUMNS partitioning enables the use of multiple columns in partitioning keys. All of these columns are taken into account both for the purpose ...The permitted data types are shown in the following list: All integer types: TINYINT, SMALLINT, MEDIUMINT, INT (INTEGER), and ...
https://dev.mysql.com/doc/refman/5.7/en/column-indexes.html
The most common type of index involves a single column, storing copies of the values from that column in a data structure, allowing fast lookups for the rows with the corresponding column values. For additional information about column indexes, see ...The B-tree data structure lets the index quickly find a specific value, a set of values, or a range of values, corresponding to operators such as =, >, ≤, BETWEEN, IN, and so on, in a WHERE ...
https://dev.mysql.com/doc/refman/5.7/en/silent-column-changes.html
In some cases, MySQL silently changes column specifications from those given in a CREATE TABLE or ALTER TABLE statement. See Section 8.4.7, “Limits on Table Column Count and Row Size”. Columns that are part of a PRIMARY KEY are made NOT NULL ...
https://dev.mysql.com/doc/refman/5.7/en/creating-spatial-columns.html
MySQL provides a standard way of creating spatial columns for geometry types, for example, with CREATE TABLE or ALTER TABLE. Spatial columns are supported for MyISAM, InnoDB, NDB, and ARCHIVE tables. Use the CREATE TABLE statement to create a table ...See also the notes about spatial indexes under Section 11.4.9, “Creating Spatial ...