• How to add Scrollview constraint in IOS Xib file


    When I started using Scrollview, I first tested it in Xib, and I couldn’t slide after adding sub layout. Later, after many attempts to solve the problem, I just recorded the process of my own solution. Step 1: add Scrollview Step 2: set up, down, left and right constraints for Scrollview Step 3:Add a contentview […]

  • Constraint Priority of AutoLayout Advanced Constraints in iOS StroyBoard


    At first, when I was working, I used SB interface development for a period of time. Later, I changed the team to pure code layout. Now for some modules of visual layout development, so summarize the original constraints of the use of methods, learn from the past. Constraint Priority As shown above, constraints 1 and […]

  • MySQL Constraint Types and Examples


    constraint  Constraints ensure data integrity and consistency Constraints are classified into table-level constraints and column-level constraints. Constraint types include: NOT NULL (non-null constraints), PRIMARY KEY (primary key constraints), UNIQUE KEY (unique constraints), DEFAULT (default constraints), FOREIGN (foreign key constraints). 1. Primary key constraints PRIMARY KEY There can only be one primary key per table The […]

  • SQLite introductory tutorial three or more constraints Constraints


    Constraints At the end of the last essay, I mentioned constraints, but there I translated them into qualifiers, which is not very accurate. Here I should correct them first, and they should be translated into constraints more appropriately. So what are constraints? When we store data in the database, some data have obvious constraints. For […]